Messages in this thread | | | Date | Mon, 10 Jul 2017 07:46:09 -0700 | From | Andi Kleen <> | Subject | Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods |
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On Mon, Jul 10, 2017 at 10:46:47AM +0200, Peter Zijlstra wrote: > On Mon, Jul 10, 2017 at 09:38:30AM +0800, Aubrey Li wrote: > > We measured 3%~5% improvemnt in disk IO workload, and 8%~20% improvement in > > network workload. > > Argh, what a mess :/
The mess is really the current idle entry path. People keep putting more and more slow stuff there, not realizing it's really a critical fast path.
> > So how much of the gain is simply due to skipping NOHZ? Mike used to > carry a patch that would throttle NOHZ. And that is a _far_ smaller and > simpler patch to do.
Have you ever looked at a ftrace or PT trace of the idle entry?
There's just too much stuff going on there. NOHZ is just the tip of the iceberg.
-Andi
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