Re: [PATCH] sched: Only migrate tasks due to interrupts on an idle CPU if prev and target CPUs share cache
From: Mel Gorman
Date: Sat Dec 16 2017 - 13:28:16 EST
On Fri, Dec 15, 2017 at 09:38:06PM +0100, Mike Galbraith wrote:
> On Fri, 2017-12-15 at 16:52 +0000, Mel Gorman wrote:
> > It's a small improvement...
> From my log on corr.arch.suse.de (2x8 box)
> Throughput 2665.88 MB/sec 8 clients 8 procs max_latency=21.472 ms
> 4.15.0.g2db767d-default NO_WA_IDLE
> Throughput 3416.35 MB/sec 8 clients 8 procs max_latency=9.825 ms
> Not so small improvement. WA_IDLE ripped corr up pretty bad, turning
> it off restored 4.4 performance.
Sounds plausible. I expect it depends on the remote access latency as
well as whether the data gets prefetched fast enough.