When the Unix load average was added to Unix

https://utcc.utoronto.ca/~cks/space/blog/unix/LoadAverageOrigin

by sciurus • 11 years ago

96 17 11 years ago

utcc.utoronto.ca

schoen• 11 years ago

I'm one week older than the Unix load average!

Or perhaps: my reported uptime is guaranteed to be longer than any Unix system's. :-)

wobbleblob• 11 years ago

Really, you have never been rebooted?

piyushpr134• 11 years ago

no. he just sleeps :)

nekkoru• 11 years ago

Barring some kind of medical emergency requiring CPR, it's safe to say quite a lot of people have never been rebooted.

rusbus2• 11 years ago

Given how hard it is to determine what is actually causing high load sometimes I'm surprised we haven't evolved more easily actionable metrics.

mjevans• 11 years ago

You mean like per process time spent active on a CPU?

You could poll that ever so often and log the results to a database if you actually cared; but the act of measuring changes the results...

dmit• 11 years ago

Or as Bryan Cantrill put it:

  When you're in top, what's the top process?
  top!
  "Hey man, good news, I've found the problem!
  I'm the problem!!
  Who would've thought that?!
  Don't run me!"

rusbus2• 11 years ago

I mean finding the actual cause of a high load number. There's no way to break it down by process, or even find out if it's because of IO or network, etc. without using other tools.

feld• 11 years ago

And don't forget that load average means something different between each OS

sciurus• 11 years ago

Also of interest is "Understanding the (original) meaning of Unix load average"

https://utcc.utoronto.ca/~cks/space/blog/unix/LoadAverageMea...

dws• 11 years ago

If memory serves, the load average calculation was the only use of floating point in the BSD 4.2 kernel. Reworking the algorithm to get 4.2 running on the National 32016 before the floating point co-processor was available was my first time inside the kernel. Fun times.

When the Unix load average was added to Unix

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