Microsoft fixes 5-year-old Defender bug, reducing Firefox-related CPU use by 75%

https://bugzilla.mozilla.org/show_bug.cgi?id=1441918

by ylere • 3 years ago

1163 417 3 years ago

bugzilla.mozilla.org

MuffinFlavored• 3 years ago

What apps other than Firefox might this have affected that badly (75% CPU usage)?

xnx• 3 years ago

I'm hoping that this fixes other apps, because Defender active scanning is a huge and near constant strain on my CPU.

snerbles2• 3 years ago

Newer versions of Thunderbird have been rendered completely unusable unless I exclude %userprofile%\AppData\Local\Thunderbird from real-time scans.

Avamander• 3 years ago

Thunderbird is atrociously slow even without an AV with any mailbox that isn't tiny. Could it be that yours has just grown over the years and Defender amplifies it?

Culonavirus• 3 years ago

All of them? From IDEs through games to email clients. Remove that malware as soon as you can. Either replace it with some more competent antivirus (not sure there are any) or don't use any antivirus at all - as a visitor of this site you should generally know what you're doing and what is and what isn't safe. I use https://github.com/jbara2002/windows-defender-remover and have been running my Windows machines without any antivirus and without any issue for years (if you ask how do I know Defender sucks if I don't run it - I do run it at work where I can't remove it - only disable it temporarily and it turns itself on again after a while).

rzzzt• 3 years ago

Eclipse and IDEA both have tickets dedicated to Defender's shenanigans: https://github.com/microsoft/java-wdb/issues/9

CWuestefeld2• 3 years ago

It's not clear to me if it's the same bug, but recent conversation here about this issue had this to say [1]:

It also has a bug(?) which makes method calls 100x slower in PowerShell 7: https://github.com/PowerShell/PowerShell/issues/19431

[1] https://news.ycombinator.com/item?id=35459984

agloe_dreams3• 3 years ago

I had an issue in early builds of W11 with use of WSL 2 & Node, Github and VS Code. Something in the git change detection process caused Defender to decide it just decided it wanted 100% of a single thread on the 5600X system I was using. While coding it would just have a core screaming at well over 4Ghz. Just all of Mankind's greatest innovations that lead to 7nm lithography and incredible processor design just to be a space heater. I never did get it figured out at the time. It also re-enables itself. So that's cool.

fsfod• 3 years ago

I would think anything with a JIT that is toggling the page protection for machine code many times a second, based on a very quick reading of the bug report talking about VirtualProtect calls and the processing of ETW events for them by defender.

sfink2• 3 years ago

I don't think anything is toggling them back and forth, it's just that a lot of chunks of executable code are being produced. But I could be wrong; maybe if you have space left for more code on a page, you'll toggle it off and append some new code, then toggle it on again.

My guess is that this would mostly come from inline caches (ICs), since they're typically small and a lot of them are generated.

sfink2• 3 years ago

Defender (or other AV) can slow down a lot of things, but in terms of the exact way that Firefox ran into it, the other apps would be anything with a JIT. Well, a JIT that uses memory protection as a security measure, though that's very common. (After generating executable code, the JIT marks the pages as executable but non-writable, so an attacker can't change the code after it starts running.)

Although the V8 JIT stopped using this, at least in some configurations (?), for the stated reason that it's not perfect—another thread could sneak in and modify the executable code in between when it was generated and when it is protected in preparation for execution. They're instead planning to rely on memory protection keys, which should be faster and more robust, but are only available on some hardware.

JITs can show up in unexpected places. Regular expression engines will sometimes have a JIT.

So... I don't know?

gtop32• 3 years ago

I would like anyone that considers Microsoft to be a recent champion of Open Source to reflect on corporate doublespeak. It's plausible that this bug was engineered as an attack on Firefox.

DoctorOW• 3 years ago

Devils advocate, why then did they fix it?

mistrial9• 3 years ago

slow walk.. or.. in comparison, have you contacted your local city government to fix obvious holes in the road recently? Around here, a two-year wait time to fix it is common.

justinclift• 3 years ago

Because it became public knowledge that it was happening?

princevegeta89• 3 years ago

Very interesting point. They might have had the intentions of pushing everyone to use Edge, and it is not surprising after their so many consistent nags and misleading messages to think its the "better" browser compared to anything else.

maccard4• 3 years ago

Have you any semblance of proof of this?

By the looks of it took Firefox a few years to figure out what the repro was, they reported it to MS, it was (very) promptly fixed and they were warned that the syscall they were using isn't being used as intended and they should consider changes to FF for future use cases.

mrb• 3 years ago

It's the AV that was calling TdhFormatProperty(), not FF. The problem was mostly on the AV side, not FF. FF itself was generating many events due to too many VirtualProtect() calls which in itself was only a smaller part of the problem.

xutopia• 3 years ago

I've lived through the browser wars and I can tell you that this would not surprise me one bit.

JustSomeNobody• 3 years ago

> It's plausible that this bug was engineered as an attack on Firefox.
Have you any semblance of proof of this?

Does it need proof? Someone can make a statement like this solely based upon past behavior. They're merely stating that it is plausible.

gtop32• 3 years ago

I don't have proof. I'm presenting a theory based on circumstantial evidence. I think it says just as much to reject a theory without proof as it does to present a theory without proof. Let me break down the context in which I make put forward my theory.

* Corporate doublespeak is a well documented tactic in which a business will project a message when the truth is the opposite of the message. Sometimes they use euphemisms, ambiguity, or omissions. I am stating that we cannot take Microsoft's press releases about being Open Source friendly at face value.

* Five years ago Edge was rebuilt with a chromium backend and Microsoft had a large campaign to increase adoption of Edge.

* Reduced Firefox performance would make Edge compare more favorably. This error was clearly in Microsoft's favor.

* It is common for companies that own a platform to create advantages for their applications running on the platform.

* Microsoft has a long history in the browser wars, highlighted by an antitrust lawsuit in the late 90s. Their anticompetitive behavior regarding browsers was a key part of the lawsuit.

vntok4• 3 years ago

What a weird take. If this bug was engineered as an attack on Firefox, then it seems like the project has been infiltrated by bad actors, because the bug comes from Firefox's codebase. Indeed, the developers themselves contradict your comment in the linked bug conversation:

This problem has two sides: Microsoft was doing a lot of useless computations upon each event; and we are generating a lot of events. The combination is explosive. Now that Microsoft has done their part of the job (comment 82), we need to reduce our dependency to VirtualProtect.

(https://bugzilla.mozilla.org/show_bug.cgi?id=1441918#c90)

Compare how many calls other browsers make (this is also quoted in the link): Firefox was generating up to 46 times more (costly) events than Chrome. It is a bit ludicrous to shame Microsoft for the whole situation.

Firefox with normal configuration: ~14000 events, 98% of which are PROTECTVM_LOCAL;
Firefox with the preferences from comment 83: ~6500 events, 95% of which are PROTECTVM_LOCAL;
Edge: ~2000 events, 91% of which are ALLOCVM_LOCAL;
Chrome: ~300 events.

stalfosknight• 3 years ago

Do we have to assume negative intent every time something like this happens?

uoaei• 3 years ago

We should at least be aware of it as an option. Many call this "healthy skepticism". It becomes unhealthy when you veer into blind optimism/pessimism/cynicism.

agloe_dreams3• 3 years ago

Well no, but I also would question the inverse. Holding accountable companies that gain from possibly bad actions and asking the questions is helpful.

See: Microsoft's Supreme court case over their preference for IE and forced monopoly. While Microsoft 'won' the case, the outcomes were exactly what the case feared but "convenient" political climate helped them avoid travelling back to court of course. Microsoft took extreme steps to avoid being broken up in the 1990s however and it's arguable that one of their political mitigation methods, investing in Apple, actually had worse effects on them. (Prior to the iPhone in 2007, it was assumed that RIM and Microsoft would be the big two players in the smartphone space, Apple and Google have basically become the big two players in the Computing space mindshare)

https://en.wikipedia.org/wiki/United_States_v._Microsoft_Cor....

chaostheory• 3 years ago

This is a relic of Bill’s tenor. Satya is different in good way.

markphip• 3 years ago

It is amusing that anyone thinks a company with > 200K employees and probably 10K products is organized enough for something like this.

naremu• 3 years ago

Inaction is a pretty low "bandwidth" form of action, and can sometimes produce the results you're looking for just as well, if not more effectively.

Microsoft has a storied history of anti-competitive views leaking to public eyes/ears, something like this is quite literally a matter of not organizing anyone.

echelon• 3 years ago

Why would Microsoft attack Firefox specifically and not Chrome? Chrome is the bigger threat to their business. Firefox has become almost too small to care about - little revenue, small browser market share.

agloe_dreams3• 3 years ago

There's an argument that Microsoft's Edge use of Chromium and then the Surface Duo would cause 'don't bite the hand that feeds you" problems. Not agreeing with OP, but it would make sense.

babypuncher• 3 years ago

This seems incredibly unlikely and overly cynical just for the sake of being cynical.

layer8• 3 years ago

Never attribute to malice…

alpaca128• 3 years ago

Nowadays a lot of malicious acts are intentionally disguised as stupidity and incompetence. Not necessarily in this case, but that quote really is showing its age.

DonHopkins• 3 years ago

If Microsoft were so good at software engineering that they could pull off such an attack on Firefox, then maybe they do deserve to have a monopoly. /s

garbagecoder3• 3 years ago

The WWEification of every discourse is the worst thing about $current-year

jeffbee4• 3 years ago

That's one way to look at it, but a very biased take. An equally valid take is that Firefox was calling an expensive platform feature too often, and even though it has been killing performance for years (possibly, for the entire history of the project) nobody noticed or bothered to fix it on the application side.

jupp0r6• 3 years ago

The platform feature in question was normally cheap and just made artificially expensive by Defender intercepting calls to it and blocking until analysis was performed. I don't think it's the FireFox' team's responsibility to be aware of and take into account arbitrary software intercepting system calls.

jeffbee4• 3 years ago

Windows Defender real-time protection is enabled by default.

vntok4• 3 years ago

I don't think it's the FireFox' team's responsibility to be aware of and take into account arbitrary software intercepting system calls.

Per the bug report, Firefox was generating up to ~14,000 calls where Chrome was generating ~300, though.

Surely it is Firefox' team's responsibility to use system calls in a sane way, say not almost 50x more than the competition?

pradn• 3 years ago

It's the application owner's responsibility to make it the app run as best as it can on a given platform. Platforms are messy, but you have to deal with it. You should escalate to the platform owner, sure, but you can't rely on them fixing it in any reasonable time-frame.

I worked on a desktop<->cloud file sync app. On Windows, only one badge can show up on a file's icon in Explorer. If there's multiple apps trying to set the badge, who wins? Well, it depends on the lexicographical order of the registrants names. So what did we do? We added some spaces to our registration name to make them show up first. Good for the user, as best as we can know - since the user or their admin had to install the app to get these badges in the first place. And they were useful ones too - whether a file was synced or not. We tried our best, and escalated.

shadowgovt6• 3 years ago

I don't think it's the FireFox' team's responsibility to be aware of and take into account arbitrary software intercepting system calls.

One of the first, hard lessons I had to learn about web development (like, stare-at-a-wall-and-consider-my-career-hard) is that web development is way more about network effects than application architecture.

Real people run systems with real configurations, and when you're targeting "the public" as your userbase you must account for that. And Mozilla knows this: if you go into the source code (circa 2009, YMMV) and look through the initialization and boot-up logic, you would find places where the system used heuristics to figure out whether some extensions had been installed in odd places instead of the "Extensions" directory (because the tool had been installed before Firefox) and hot-patch paths to pull in that component. Because if a user installs Flash and then installs Firefox and Flash doesn't work in Firefox, it's not Flash that's broken... It's Firefox.

It doesn't matter if the bug is in "Microsoft's code" or "Mozilla's code." That's unimportant. If you're a Mozilla engineer, all that matters is whether this bug would cause a user to get pissed off and uninstall Firefox.

Thats. All. That. Matters.

rrrrrrrrrrrryan• 3 years ago

arbitrary software

Windows Defender isn't "arbitrary software" - it's built into the OS and enabled by default. To anyone building an application for Windows, it should be considered part of the platform.

jupp0r6• 3 years ago

Also worth noting that the "expensive platform feature" you refer to in this specific case means "writing to a file". Something as basic as this should be assumed to be fast on modern operating systems.

jeffbee4• 3 years ago

It is not a bug that there are overlooked optimizations in some platform features. Windows has a ton of slow features. Starting a process, for example, takes forever. It is the responsibility of application authors to write their performance-sensitive critical path in such a way as to avoid bogus platform behaviors. This goes for Linux, which has more than its fair share of brain damage, as well as Windows.

vntok4• 3 years ago

Yeah, your program definitely should not do as many useless writes on the system it runs on, it's just bad behaviour. If every program did the same the disk would grind to a halt, SSD or not.

pavon• 3 years ago

No it had nothing to do with Firefox writing files. Firefox was making a bunch of calls to VirtualProtect. Windows Defender (MsMpEng.exe) was then writing to file (an sqlite database) every time one of these calls was made, which was slowing down the system.

This comment is a good summary of what the issue was once they understood the problem: https://bugzilla.mozilla.org/show_bug.cgi?id=1441918#c82

CWuestefeld2• 3 years ago

Recent discussion of this here also cited a problem (not sure if it was the same problem) with Defender causing 100x performance drop with some PowerShell operations.

jesse__4• 3 years ago

I'm not sure how you can possibly qualify VirtualProtect as "an expensive platform feature". Looking at the operation that VirtualProtect actually has to perform, from first principals, it should be one of the cheapest syscalls in the entire kernel.

The bug was that ETW (in the antivirus process) was doing something braindead; zeroing a megabyte of memory unnecessarily every time someone called it just to get the size of a buffer.

kramerger3• 3 years ago

it should be one of the cheapest syscalls in the entire kernel.

That's an educated guess... that is unfortunately very easy to disprove :(

shadowgovt6• 3 years ago

Branch prediction should be a super-dumb algorithm, but then Spectre comes along and, oh dear.

Malware protection algorithms make fools of us all.

dgellow• 3 years ago

mpengine.dll version 1.1.20200.4 was released on April 4, so the fix should be available for everybody now. See the end of comment 91 to know what version you are using. Also, the latest discoveries in bug 1822650 comment 6 suggest that we can go even further down in CPU usage, with all antivirus software this time, not just Windows Defender.

Really nice to see open collaboration between Mozilla and Microsoft development teams resulting in a net improvement for everybody.

bornfreddy2• 3 years ago

Yes. I mean it took 5 years, but who would count. /s

dan-robertson• 3 years ago

People care about open Firefox bugs much older than that. Basically any long-lived program will have ancient bugs that never made it onto someone’s todo list.

hgsgm3• 3 years ago

Well, a net improvement for the people who paid Microsoft for an OS that wasted their energy and wore down their computer (heat damage) for 5 years.

Dalewyn2• 3 years ago

I'll note that mpengine.dll was updated for me on Windows 11 Pro 21H2 in spite of my blocking autoupdates via Group Policy.

To be clear: I'm aware Windows Defender updates itself independently of Windows Update, and I actually don't mind and even appreciate this behaviour since Defender updates almost always aren't intrusive unlike the rest of Windows Update.

Just an FYI for people with similar configs.

0x4c6565• 3 years ago

This update is causing intermittent browsing issues in Firefox and Chrome for me and several others (not Edge, though). Getting 'PR_END_OF_FILE_ERROR' in Firefox, with Chrome experience issues at the same time (though Chrome does eventually load the page)

crest• 3 years ago

"bug"

tcfunk• 3 years ago

I wonder if this is why Firefox often gets killed when I have other high-resource apps open?

whalesalad3• 3 years ago

My only interaction with Windows Defender is the (undefeatable) nag popup every boot that warns me it is disabled.

badrabbit2• 3 years ago

Haha, you should enable it with exclusions. It's the best AV out there that isn't an EDR. I disable it in labs but I can't imagine running windows in prod with defender enabled. Don't use windows like it's Linux.

TecoAndJix• 3 years ago

Defender, under certain licenses, is an EDR - https://learn.microsoft.com/en-us/microsoft-365/security/def...

ChuckNorris894• 3 years ago

My car also nags me every time I unbuckle my seatbelt to park yet that doesn't mean everyone should have it unbuckled all the time. There's a reason it's designed to be naggy.

Having everyone easily disable Windows Defender will not lead to a great outcome.

There's a reason malware on Windows has been on a steep decline from the Windows XP days and I'd prefer it to keep it that way.

whalesalad3• 3 years ago

TBH the main reason I commented this was to get some kind of validation from the community (positive or negative). Sounds like I need to turn it back on :)

I really only use this machine for MWII, Halo and Titanfall. It's a glorified Xbox. I even contemplated putting it on a standalone VLAN to 100% physically isolate it from my core net.

akira2501• 3 years ago

Not all uses cases for a car are the same. Some are held entirely on private property and are used as work vehicles where the seat belt chime would be unnecessary and distracting. Which is why most manufacturers provide a sneaky mechanism to disable it. I own the vehicle, why wouldn't they let me disable the nag?

Their solution? Make it intentionally complicated, but still possible:

Step 1: Turn your headlight switch off

Step 2: Unbuckle your seatbelt and turn the key to the off position

Step 3: Turn your key to the on position till the seatbelt warning light turns off

Step 4: Buckle and unbuckle the seatbelt three times and end on the unbuckled position

Step 5: Turn your headlight switch on for three seconds and then turn it off

Step 6: Repeat step number 3

Step 7: Wait for the seat belt warning light to turn on and off again then buckle and buckle the seat belt

Renaud• 3 years ago

If you use Windows Pro and Enterprise, you can use GPO to disable Defender. Just run gpedit.msc and edit a few of the policies to disable real-time protection etc.

Under Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus

  - Turn off Microsoft Defender Antivirus -> set to Enabled

Under Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus > Real-Time Protection

  - Turn on behavior monitoring -> set to Disabled
  - Monitor file and program activity on your computer -> set to Disabled
  - Turn on process scanning whenever real-time protection -> set to Disabled
  - Turn on behavior monitoring  -> set to Disabled

Restart the computer and Real-time protection should be disabled permanently (until you reverse the same settings through gpedit.msc at least).

bob1029• 3 years ago

You can also elevate to Trusted Installer or System and completely remove this garbage from your computer.

Alternatively, if you run windows server as your workstation OS, you can perform an uninstall using Remove-WindowsFeature from powershell.

The old gpedit tricks don't really work anymore in my experience.

zamadatix3• 3 years ago

With 11 (or possibly newer versions of 10, haven't tried lately) this doesn't seem to actually disable MsMpEng.exe from loading anymore. Using something like https://github.com/jbara2002/windows-defender-remover seems to work though.

garbagecoder3• 3 years ago

It’s humbling to be in the presence of such greatness.

arnaudsm2• 3 years ago

Quick napkin math of the wasted power : Firefox has ~300e6 users, let's assume the bug wasted 5 extra watts 4 hours a day.

That's 250 megawatts saved, the equivalent of an average coal power plant. Because some Microsoft engineer missed a bug.

chillstreem2• 3 years ago

doesn't this bug only manifest itself if one is using microsoft defender as their only security solution, and not a 3rd party AV/IS? if so, then the number of Firefox users in this calculation is much lower.

SketchySeaBeast2• 3 years ago

I don't know if that's the case. I'm a Firefox user but consider all the 3rd party apps nearly as much malware as the things they are trying to solve. I run strictly defender and try to make good choices when downloading and browsing.

Neil44• 3 years ago

More complicated still, defender does not completely stop working when 3rd party AV is installed. Also maybe Firefox is not the only app triggering this bug?

slowmovintarget• 3 years ago

I run an antivirus suite and have attempted to turn Defender off several times. Windows Update keeps switching it back on.

recursive3• 3 years ago

The units don't make sense. You might mean megawatt-hours?

hgomersall• 3 years ago

It was not so well explained, but the GP does mean averaged over 24 hours, the power requirement is 250MW.

arnaudsm2• 3 years ago

No typo, I meant Watts. I averaged the 4 hours per day

teraflop• 3 years ago

No, it makes sense. The parent is talking about continuous power measured in megawatts, i.e. megawatt-hours per hour, or megawatt-days per day.

300 million users * 4 hours/day * 5 watts = an average continuous savings of 250 MW.

xdavidliu• 3 years ago

one way it could just be mW is if he/she meant “a coal power plant for the 5 years that the bug was active”

ChuckNorris894• 3 years ago

You assume all Firefox users are on Windows (they're not) and that all Firefox users on Windows are affected (I and my SO were not).

Who knows what edge case triggered that bug to manifest but I for one haven't seen it in the wild in the years we've been using FF.

Probably difficult in such a large org to allocate dev resources to chase down and fix a bug few people were impacted by.

callahad• 3 years ago

Around 80% of Firefox users are on Windows, per https://data.firefox.com/dashboard/hardware

That same site also suggests that Firefox has around 200e6 monthly active users, the average user uses Firefox 3.5 days a week, and for 5.5 hours per day.

My math could be wrong, but taking the above into account, and arnaudsm's 5 W estimate, I come up with an upper bound of around 80 MW. Discount that further by whatever proportion of Windows users you assume were actually affected. Not a whole coal power plant, but nothing to sneeze at.

pjmlp• 3 years ago

If it isn't on the Sprint board it doesn't exist.

dylan604• 3 years ago

You also have to assume that at least one Microsoft employee has Firefox installed. There's no bug if there's no users

duxup• 3 years ago

the equivalent of an average coal power plant

Produces in an hour, four hours?

lordnacho• 3 years ago

Continuous. We need one less coal plant to support the Firefox code after the bug fix.

rimunroe• 3 years ago

I'm pretty sure you're mistaking power for energy. Watts are units of power, which is the rate of change in energy (joules per second). Asking for how much power something produces in an hour is like asking how many miles per hour your car goes in an hour.

jonhohle• 3 years ago

I love calculations like this and hope they are part of every engineer’s line of thinking. I originally came across this thinking in Andy Hertzfeld’s book - https://www.folklore.org/StoryView.py?story=Saving_Lives.txt

Performance is time, energy, heat. It’s one of the easiest features to get and there are lots of tools, research, and philosophies to help get it. Memory and storage are similar.

For anyone working on large scale apps that are on millions of devices, hundreds of thousands of servers, or even just some back office guy who has minutes less stress in his day, performance benefits the world. For programmers, it’s one of the easiest ways to Save the Planet™.

RodgerTheGreat• 3 years ago

It can be a bit dangerous (especially to your employer) to continue that line of thinking, though. How many pieces of software do we collectively work on which would make the world a better place if they didn't exist at all?

harshreality2• 3 years ago

How did the idea of avoiding premature optimization get misapplied to client-side apps where the entity writing the software is not the one paying for electricity, cooling, and people's time when the software takes much longer to run than it could? When did a lot of software devs stop caring?

Pardon me, I think there are some electron devs at my door asking for a word. They might have baseball bats.

sseagull• 3 years ago

Don't forget the waste caused by people throwing away devices that are "too slow", and the resources required to build new computers/phones.

Somewhere I saw a rough figure about phones. Something like: if everyone was able to keep their phone one year longer, it would be the equivalent of 600,000 cars off the road or something. (Just looked it up - source is possibly the founder of iFixit).

But you know, development velocity or whatever.

zerocrates• 3 years ago

There's a similar calculation (in a slightly different context) in a good scene in the movie Margin Call, about all the miles and hours saved by one bridge: https://www.youtube.com/watch?v=m8Mc-38C88g

sdfghswe• 3 years ago

let's assume the bug wasted 5 extra watts 4 hours a day.

How did you come to this?

mrinterweb• 3 years ago

Great question. Based on my use, it would be a lot more than 5 watts/day.

schemescape• 3 years ago

Yes, the trace comparison in the link (which the author says is for browsing YouTube in Firefox) shows average CPU usage is down from roughly 5% to roughly 4%. That’s a great improvement, but I’d like to know why we should assume that translates to 5 Watts.

HPsquared• 3 years ago

Would be interesting to see the energy usage of Windows Update computed in a similar way.

cutler• 3 years ago

Don't underestimate Microsoft Won’t Fix which helped IE dominate the browser market for over a decade.

perfmode• 3 years ago

user must be running windows

dist-epoch• 3 years ago

That's 250 megawatts saved, the equivalent of an average coal power plant. Because some Microsoft engineer missed a bug.

Are you sure you want to invoke this logic? Because following it through imagine the energy savings if Firefox users switched to Chrome.

axolotlgod• 3 years ago

Does Chrome really use significantly less resources than Firefox? Are there numbers there?

LeoPanthera2• 3 years ago

Are you sure you want to invoke this logic? Because following it through imagine the energy savings if Firefox users switched to Chrome.

Ironically, Mac users routinely complain about how power-hungry Chrome is on the Mac. Safari is significantly more efficient.

ChuckNorris894• 3 years ago

Or the energy used by all the electron apps on all operation systems.

airza• 3 years ago

There are good reasons to not use chrome over firefox, but few reasons to leave firefox bugged. I don’t think the same utilitarian logic applies.

omneity2• 3 years ago

It's not too bad an analogy. Think of it this way:

- Switching from Firefox to Chrome might be similar to switching between two car models, one consuming less energy than the other.

- Fixing this bug is more like going to a car workshop to fix an injector issue in your car that was causing higher fuel consumption and more pollutants.

The first one is really a matter of tradeoffs and personal choices. The second one is less of a choice and more of an actual issue that was left due to negligence. Hardly similar.

lotsofpulp• 3 years ago

The cause and effect exists whether or not some commenter on HN writes about it.

The reason it is not “invoked” is because energy prices are sufficiently low (due to not pricing in externalities) that there exists little incentive for end users to optimize for power usage.

lkbm• 3 years ago

I mean, sure, I could also just turn off my computer. Presumably people use Firefox for a reason, and making that a option use less energy is pure upside, and it's very interesting to see how big of an upside it might be.

volkk• 3 years ago

Because following it through imagine the energy savings if Firefox users switched to Chrome

i've read everywhere that Firefox at this point is far more energy efficient than Chrome...is that not true?

Georgelemental2• 3 years ago

If one user switches to Chrome, the energy savings are only for that one user. If one Microsoft engineer fixes a bug, the energy savings are for the many thousands who use Firefox on up-to-date Windows.

kramerger3• 3 years ago

imagine the energy savings if Firefox users switched to Chrome.

Nah, I like my privacy. How about replacing Electron apps with native apps instead?

ouid• 3 years ago

Using firefox without memory errors is a pareto optimization over using firefox with memory errors.

tgv• 3 years ago

Think more like this: this bug cost an average coal power plant, all other things being equal. I doubt it's that much, but it certainly did waste a lot of energy.

imagine the energy savings if Firefox users switched to Chrome.

Imagine the privacy savings if Chrome users switched to Firefox.

shapefrog3• 3 years ago

imagine the energy savings if Firefox users switched to Chrome

This is why I left firefox.

tyingq• 3 years ago

Maybe compare manifest v2 friendly Firefox with uBlock Origin vs eventual Chrome without it :)

xxs• 3 years ago

Firefox users switched to Chrome.

Far worse due to privacy/adblock addons.

wiseowise2• 3 years ago

Because following it through imagine the energy savings if Firefox users switched to Chrome.

Enlighten us.

harry8• 3 years ago

Imagine the power savings if chrome users switched to lynx.

Imagine the power savings if everyone used pihole, ublock etc.

Second uses more power than the first and is better. Do it!

hanoz• 3 years ago

imagine the energy savings if Firefox users switched to Chrome.

Imagine the energy squandered on all the extra goods and services bought by users using a browser owned by an advertising company, instead of Firefox.

everdrive• 3 years ago

Now do one for javascript.

mr_toad• 3 years ago

Are you sure you want to invoke this logic? Because following it through imagine the energy savings if Firefox users switched to Chrome.

And then imagine Safari on an M1.

viraptor• 3 years ago

It works for a single case, but not sure about long term. We still have at least a little bit of competition. All browsers improve because the other ones improve. If we all switched to Chrome or Safari because of the power saving, we'd just get another version of IE monopoly/stagnation which could result in more power wasted longterm.

The optimum is likely somewhere where most people use the currently most efficient solution and others keep alternatives alive and competitive.

midoridensha• 3 years ago

Imagine the energy savings if all users installed a good ad-blocker.

michaelcampbell• 3 years ago

How many megawatts saved if everyone learned how to do all their work on text-only consoles running linux?

rhaway84773• 3 years ago

Those are 2 very different things.

In switching browsers, you get different features, workflows and functionality, many of which you prefer on Firefox, which is why you’re using it.

With this bug fix, there is absolutely no loss or change in functionality (other than increased battery life), and yet you’re getting the benefits.

This bug is pure waste.

marricks• 3 years ago

Because some Microsoft engineer missed a bug

That might be a bit too kind given how much Google liked to Oops Firefox. Wouldn't be surprised if MS did too.

Oops:

https://www.computerworld.com/article/3389882/former-mozilla...

zerkten2• 3 years ago

This is just one bug in the world affecting power usage with Firefox. There are loads more like https://bugzilla.mozilla.org/show_bug.cgi?id=1404042 which caused me to abandon it on macOS as my primary browser.

chlorion3• 3 years ago

Gaming on a mid-tier modern GPU probably uses around 50-100w, the Steam stats probably have a number of users to multiply with. I'm sure it's a massive amount of power.

I don't like video games and they are not-necessary so I propose that we ban them globally, or only allow gaming if using renewable energy. If you don't live in a place where this is an option, too bad!

Maybe instead of this we require all games to be limited in graphical effect (imagine early source games or something). We could save a lot of power globally if we enforced this.

This is why I strongly dislike this line of thinking. I don't think power plants work that way anyways, they probably make a constant-ish amount of power rather than taking exactly 50w worth of fuel every time someone opens up Call Of Duty.

There are also much lower hanging fruit to get upset about if you care about the planet, like cars with large motors or people with heated drive ways (yes thats a thing).

ericye16• 3 years ago

This is a bad comparison, gaming presumably brings utility to someone whereas this was a pure bug with no upside.

kortilla2• 3 years ago

People get entertainment out of games. They got nothing out of this wasted cpu.

cassepipe• 3 years ago

Now I will have to spend the rest of my life to try to forget that heated driveways are a thing and pretend everything is going to be fine

vinyl7• 3 years ago

I have been hoping for many years that global warming would force devs to go back to a time of creating fast and efficient software in order to help the environment.

Unfortunately devs dont realize how needlessly power hungry software is when they don't need to be. But hey, its easier to use electron and javascript than it is to save the planet.

tinglymintyfrsh2• 3 years ago

It's 5.5 MW.

That's not how power or energy works.

5 [W*hr/day] (Kept in energy units per interval rather than average power).

200e6 users/day who surf for maybe 4 hours/day

5 * 200e6 * 4 / 24 = 133 [MW*hr/day] (133/24 = 5.5 MW)

A typical US home uses 11 [MW*hr/y] or 0.36 [MW*hr/day].

(Convert to power draw, that's 0.015 MW.)

mean consumption of roughly 400 US homes (133 / 0.36).

The smallest US grid-tied operational nuclear power plant produces 600 MW. 133 MW very small coal power plant would 400 MW.

https://data.firefox.com/dashboard/user-activity

sesqu• 3 years ago

Your math is wrong.

  5W/user * 200e6 user * 4h/24h = 167 MW
  11 MWh/a/home = 0.00125 MW/home
  167 MW / (0.00125 MW/home) = 133 000 home

docmars• 3 years ago

While this feels significant, I don't think humanity is doing itself any favors by guilting itself over problems it didn't (or couldn't) anticipate. Hindsight is always 20/20. This is especially true when "don't over-optimize" is a core tenant in software development. Software would never ship in a reasonable timeframe if we scrutinized every release to this degree during development.

taeric2• 3 years ago

Only works if this was a constant drain for everyone, though? If it only saves 100 watts once a month, from a quarter of users, things change. A lot.

tgsovlerkhgsel• 3 years ago

Takeaway: If you're working for a tech company with billions of users, your personal CO2 footprint is completely irrelevant. Rather than agonizing over flights vs. trains, beef vs. pork vs. vegan alternatives, heating etc. - find some small thing that you have access to and that you can optimize.

That's about 2.2 TWh per year. A decent estimate for average worldwide CO2 intensity of electricity is 400 gCO2e/kWh (that's 400 tons per GWh). A typical personal footprint including some international flights will be in the tens of tons.

MyelinatedT• 3 years ago

It's worth considering that not all Wh are equal in environmental impact. In the case of many (most?) big tech firms, a large proportion of their energy consumption is sourced from renewable sources.

b3lvedere• 3 years ago

Imagine what could have been saved if you stop loading ads in your browser.

drumttocs8• 3 years ago

How are you calculating 5W? And subsequently 20Wh?

Brosper• 3 years ago

Wow Microsoft should say at least sorry to Mozilla and somehow repay them for this!

neilv• 3 years ago

When I've heard people speak of changing Web browsers in recent years, I think the two most common reasons given are performance and privacy.

I wonder whether this situation with Microsoft Defender cost Firefox some market share.

dalmo3• 3 years ago

I can count at least one user that Firefox lost to this bug. Pretty happy with Brave now, won't even bother trying FF again.

andrewstuart• 3 years ago

DOS ain’t done till lotus won’t run.

NelsonMinar2• 3 years ago

It's so frustrating this discussion took five years.

I'd be grateful for an overview of the bug. I don't think I've seen it on my two systems but I can't be confident.

stronglikedan• 3 years ago

Five years is nothing for MS. You should see how long the bug in File Explorer has been there, where after navigating to a folder and pressing the down arrow, the second item is selected instead of the first. And it's one of those things that, even though I'm aware of it, it still always catches me causing extra keystrokes. It's like they're trying to force me to use the mouse for some reason.

zamadatix3• 3 years ago

That one I can almost agree with the reasoning for. The first item is selected by default but also by default you have to intentionally trigger a keyboard navigation for it to go into that mode since most don't intend to do that when hitting enter on a freshly loaded directory. As evidence of this behavior instead of hitting a directional key to change the selection whacking space should activate the highlight on the first item and then another navigation action is needed to actually do anything.

I think it'd be more convenient (for me as a keyboard centric user at least) if it were done differently but I don't think it's actually a bug as much as an intentional decision at the cost of keyboard user. This is unlike the Defender issue where it's of no purpose to be significantly slower than it needed to be.

forgotmypw17• 3 years ago

I think you can press Space to select the first item.

recursive3• 3 years ago

That doesn't particularly sound like a bug. There may be varying opinions about whether it's good or not, but it kind of almost makes sense to me.

bsder• 3 years ago

Windows Update and Windows Defender are notorious piles of shit that eat up huge amounts of CPU for seemingly no reason.

The problem is that there is zero incentive to get them right. Nobody is going to get promoted because they use 10% less CPU. Nobody is losing their bonus because 10% of all computers melt down. etc.

jesse__4• 3 years ago

This bug would suggest that ETW is actually the giant pile of shit.

Which, in my experience, isn't far from the truth.

Other people think so too: https://caseymuratori.com/blog_0025

Animats• 3 years ago

How fast would this have been fixed if was Microsoft Edge that was wasting CPU time?

jahsome• 3 years ago

Depends on how fast google patched it.

MagicMoonlight• 3 years ago

“Bug”

subarctic• 3 years ago

When you say reduced by 75%, would that mean, say, going from %40 to 10% or from 75% to 0%?

chucksmash• 3 years ago

It means the former.

If you reduced something to zero, you reduced it by 100%.

nabakin5• 3 years ago

https://news.ycombinator.com/item?id=35458746

@dang

GrumpyNl• 3 years ago

maybe AI helped them out.

nabakin5• 3 years ago

Firefox-related CPU use is only reduced by 75% when this bug is caused. NOT in the general case as this title implies

yarg• 3 years ago

That's actually fairly clear in the title - the second clause depends upon the first.

nabakin5• 3 years ago

Then why are comments assuming a large decrease in power consumption?

cronix2• 3 years ago

If you're on a Mac and using FF (probably not FF specific), turning off "ambient mode" in youtube can save 30% cpu. I just found this out while searching why FF was taking 90% of my cpu while watching youtube videos in normal mode, but went down to 40% use if viewing in full screen. Turns out that this youtube "ambient mode" was the culprit. My lap is now cooler and the fan doesn't turn on anymore. I wonder how much power I've wasted due to this new "feature" they added 6 months ago that I didn't know about.

emoII• 3 years ago

Same behaviour for me using Safari.

winter_blue• 3 years ago

This is one of the myriad reasons why I have a strong preference for Linux.

fiddlerwoaroof• 3 years ago

This has nothing to do with macOS vs. Linux, though

ezfe• 3 years ago

not sure what your point is... ambient mode is a visual effects thing YouTube does and reading the descriptions, not surprised it causes increased CPU usage regardless of OS.

DevKoala• 3 years ago

Something happens

This is one of the myriad reasons why I have a strong preference for Linux.

ok_dad2• 3 years ago

I just bought a Macbook because my dedicated Linux laptop, made by a popular Linux-only manufacturer, had so many issues that I got tired of diagnosing. I love Linux, but it's not a panacea for every computer issue under the sun, just a few of them. I, personally, am stoked I no longer have to deal with issues with this new machine, and can just take it into a Genius bar appointment to let someone else deal with it, for pennies a day. You can't get that on Linux!

Feel free to tell me I'm a sell-out, I am happy to be one today.

sicariusnoctis3• 3 years ago

This happens on Linux too. I was wondering if the weird CPU-hogging flickering was a bug in my compositor (picom) or window manager (i3) or browser (Firefox). Turns out to be a "feature".

asvitkine• 3 years ago

To save a search:

"Ambient mode uses a lighting effect to make watching videos in Dark theme more immersive, by casting gentle colors from the video, into your screen's background."

tough• 3 years ago

They went for copying philips ambient lights on tv's but with software, what could go worng

shrewduser• 3 years ago

oh i saw this happen to me the other day, i was wondering if it was a new youtube feature or something. can't say i care for it.

bee_rider2• 3 years ago

Neat idea, I bet the intern had fun implementing it, why was it on by default?

sicariusnoctis3• 3 years ago

The "average color" (or whatever it is) could have been pre-computed server-side rather than tiring out the poor innocent client CPUs.

javajosh• 3 years ago

To save another search:

On desktop and mobile devices:

    While playing a video, select the Settings button.
    Locate the Ambient Mode setting in the list of preferences.
    Toggle it to off to disable Ambient Mode for all videos on YouTube (in that browser).

It's in the same popup used for video quality and playback speed.

tmtvl• 3 years ago

As I don't use edgelord mode I'm guessing I don't have to worry about it.

musicale2• 3 years ago

make watching videos in Dark theme more immersive

the best way to make youtube videos more immersive is to block obnoxious advertisements, remove useless algorithm-driven recommendations, and delete the comment section

JohnFen4• 3 years ago

Thank you! I had no idea this was a thing YouTube did.

thih92• 3 years ago

This is why I like terminal, rss, or other technologies where it’s hard to add this kind of fireworks to the UI.

When done right, sure, they improves the user experience by some percentage. But when done badly, the UX goes down by orders of magnitude.

tiagod• 3 years ago

If you turn off your computer power usage goes to 0% too.

xk_id3• 3 years ago

absolutely. besides, graphical UIs bombard the brain with everyone's unique take on visual aesthetics, consuming limited mental resources like attention

Tagbert2• 3 years ago

Where is that setting? In YouTube Settings? I don't see it, there.

erulabs• 3 years ago

It's not in the general settings - instead it's in the setting menu in the video player itself, where you'd select the quality and playback speed, etc.

b215826• 3 years ago

If you use uBlock, add the following to the filters:

  youtube.com###cinematics.ytd-watch-flexy

wslh• 3 years ago

I think it is time to have a way to fine tune consumption based on settings. I assume the less complex way to do this is, really, use the telemetry information gathered.

treis• 3 years ago

Similarly gifs and animated emojis in Slack chews up the CPU. Something like 20% at idle before I turned it off.

xk_id3• 3 years ago

as I don't care about the comments section or the recommender algo, I search (youtube-fzf) and launch (yt-dlp + mpv) youtube videos directly from the terminal. i have a bash pipeline for this and, naturally, it is very resource efficient

Affric• 3 years ago

post the script pretty please

hapticmonkey• 3 years ago

I honestly thought my monitor or GPU was having issues with weird colour banding around YouTube videos. Turns out it was an intentional choice they made to do that. I don’t know why it’s on by default.

waz0wski• 3 years ago

Or stop using the crap YT frontent entirely - https://yewtu.be

Run your own alternate frontend - https://github.com/iv-org/invidious

bmicraft2• 3 years ago

That site doesn't even seem to support anything over 720p, so much for crap

leeman2016• 3 years ago

Wow! didn't know that. Very helpful

zimmund• 3 years ago

To be fair this wastes CPU cycles in all platforms. And it probably took more human effort than keeping Google Reader alive FFS.

somid3• 3 years ago

Conspiracy theory — could this have been done on purpose for browser share dominance purposes?

shadowgovt6• 3 years ago

Sometimes, but probably not in this context.

a) That'd be a very untargeted way to get that effect; Firefox isn't the only app that's going to be making calls like that.

b) Mozilla doesn't need any help losing marketshare in this era.

toenailtag• 3 years ago

I would bet it is more likely that MS devs noticed but just didn't care. The farthest it would have gotten in conversation with QA triage would have been "does this issue affect any of our services? Ok then that is Mozilla's problem."

simondotau2• 3 years ago

MS?

tinglymintyfrsh2• 3 years ago

Nope. MDE is shitty. It pushes updates to millions/billions of machines without sufficient testing and monitoring.

There was a MDE bug that caused Chrome to crash whenever dragging tabs.

Another time, MDE also appeared to "remove" all of some users apps when it deleted shortcuts.

shadowgovt6• 3 years ago

Woof, that's a long time for a bug like that to have sat around and Mozilla to not have come up with a workaround for it.

dbg31415• 3 years ago

I have screamed about this like a crazy person and filed bugs and was always told, "Meh there's nothing there..."

But if you use Firefox to call yourself on Chrome... you'll see that Firefox takes up a TON more energy on an Intel MBP than Chrome does.

You can tell because Firefox literally heats your laptop up to do streaming videos. You hear the fans kick on, the laptop gets hotter to hold.

Anyway I'm sure there are more bugs like this! Glad Firefox is getting some of the people to fix their code... but look, Microsoft isn't the only culprit. Until Firefox takes as little power as Chrome in MacOS & Windows... I think we should all stay outraged! (=

jiggawatts• 3 years ago

Looks like there's more work left to do to catch up to Chrome: https://bugzilla.mozilla.org/show_bug.cgi?id=1823634

That bug is more subtle. Apparently the various ways to use VirtualAlloc is not self evident, and some variations have wildly different performance characteristics due to undocumented interactions with Event Tracing for Windows (ETW) events that get sent to anti virus products.

So it's not only the original problem of the events being handled inefficiently, it's also that the way they're generated is a bit of a black box and hard to predict without detailed performance tracing work.

pomsense• 3 years ago

Most likely their devs using GPT4 and finally "fixed" it

dang• 3 years ago

Recent and related:

Firefox engineers discover a Windows Defender bug that causes high CPU usage - https://news.ycombinator.com/item?id=35458746 - April 2023 (215 comments)

Is the current post significant new information* or just a repeat of that submission?

* https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...

mmis1000• 3 years ago

Guess that's why I never feel firefox laggy but others said it is. The first thing I do after installing windows is always installing some other antivirus to disable defender. Because the defender start routine scanning at weird time and lag games randomly, which is really annoying.

I really have no clue why engineer at ms think such behavior is ok. Shouldn't scans like these scheduled at some time slot that people are not actively using computers?

TaylorAlexander• 3 years ago

I haven't run in to this issue either. The first thing I did when I bought my windows laptop, before ever booting it, was plug in a debian installer disk and then boot to that, erase the entire drive and install debian. More windows users should try this little trick!

nnurmanov• 3 years ago

Someone should create a website to list bugs that haven’t solved for years. Hall of shame. I myself could add couple from Oracle, hibernate

wankle3• 3 years ago

Someone diverged the thread into Linux vs Mac. The point is, how did the evil Microsoft monolopy get away with not fixing this bug for so long.

taeric2• 3 years ago

I feel like this could/should be a metaphor for airport security...

xyst• 3 years ago

yet another reason why I don’t touch Windows for any professional/sensitive workflows.

Only keep a license around for the occasional gaming session. Disable all of the Windows features (ie, firewall, auto updates, antivirus) and telemetry. Strip the OS to bare minimum and manage the GPU, mobile drivers manually. Limit it to only games

qikInNdOutReply• 3 years ago

Good thing its a bug though, not a monopolistic attempt to sabotage the competition running on your platform, by doing strange things with API rodeo. This surely ruined the performance of other software too..

NelsonMinar2• 3 years ago

Interesting comment on Reddit from a Mozilla engineer: https://www.reddit.com/r/firefox/comments/12hxqjl/comment/jf...

Careful to talk about how this is entirely a fix for Windows and will improve the experience of folks using other software, not just Firefox.

PaulHoule• 3 years ago

It’s hard to say that anti-virus isn’t worse than the virus.

Microsoft fixes 5-year-old Defender bug, reducing Firefox-related CPU use by 75%

Related Stories