HN user

haricm

6 karma
Posts1
Comments7
View on HN

The original OpenCV code already has intrinsics in many portions of the code. But enabling them results only in a 10% improvement.

We decided to report non-intrinsics version, because reporting the original OpenCV numbers with intrinsics as SSE optimized would be unfair to Intel. Apparently its not very well optimized.

My own guess is that if we add intrinsics for Intel to our own C code, it will boost by around 2x. We could have written a blog without reporting the Intel C optimized numbers, but that would have been unfair to Intel again.

Yes this is correct. But as you see the original un-optimized version was running at nearly same speed on both. Meaning the A15 and Core i3 performance are comparable, if run at the same clock. The general perception has been that the raw performance of the ARM CPUs(like A15 and A57) and Intel Sandybridge CPUs like the one inside like i3/i5 are not in the same ball-park . Most people believes they are leagues apart. Also one of the reasons why such comparisons havent been made before, much.The idea of the blog is to show that this is not completely true.

Drill, I partly agree with you. But as you know ARM is getting into servers in a big way. The idea is low power servers(green servers as it is called) of course, and there are several silicon vendors already working on it. ARM recently announced Cortex-A57 and A53 precisely for this segment. The A57 can be expected to have a similar performance to that of A15, but with higher clocks. Hence this discussion, I believe, is not totally irrelevant.

We wanted to keep the clocks out of the picture. This I must admit, is a little unfair, because having the ability to run at higher clocks is indeed a capability of the CPU, which cannot be discounted. In this case I compared a Cortex-A15 Vs an Core i3. The A15s can run at max 2GHz I think. While the Core i3 cores can run upto 3GHz. However ARM has Cortex A57 coming along, which I believe will have similar performance to the A15 and will be able to run at higher clocks too. Of course we need to wait for the A57 to appear on an actual SOC and measure it, before we can truly make that claim.