Scheduler patches: 6x performance increase when system is under heavy load
From: Alexandre-Xavier LabontÃ-Lamoureux
Date: Sun Dec 11 2016 - 16:41:58 EST
There's a research paper called "The Linux Scheduler: a Decade of
Wasted Cores". It shows how the Linux Kernel scheduler is broken and
they provided fixes for some of the know issues that it has. The
changes are illustrated in a presentation that was shown during a
I patched my kernel with these patches using a simple tool. I
compiled the Linux kernel on it and I was flabbergasted to see an
estimated six times performance increase. It was blazing fast and I
couldn't believe it.
Here are my results (using "time make -j32" on my VM that has 4 cores):
Same kernel, but patched:
I hope you guys will look into this. If these changes were introduced
into the kernel, it would be great and benefit to a lot of people.
There may be some regression. People have said that it improved the
throughput of the kernel, but on some application such as games, there
are some performance spikes due to overscheduling. This already
happens in the vanilla kernel, but it's worsened a bit. Power
management will also be a thing to look into.
I hope the scheduler engineers will fix the kernel. The research paper
has been out for a while and nothing has been done yet. Personally, I
think six times is huge as someone who compiles huge projects often
and the regressions if any are not apparent to me. Other people should
try it too to test if it's good.