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
