Re: [PATCH v8 2/2] sched/fair: Introduce SIS_CURRENT to wake up short task on current CPU

[Mike Galbraith]

On Mon, 2023-05-01 at 20:49 +0200, Peter Zijlstra wrote:
> On Mon, May 01, 2023 at 05:32:05PM +0200, Mike Galbraith wrote:
> > On Mon, 2023-05-01 at 15:48 +0200, Peter Zijlstra wrote:
> > >
> > > Throughput  646.55 MB/sec   2 clients   2 procs  max_latency=0.104 ms
> > > Throughput 1361.06 MB/sec   5 clients   5 procs  max_latency=0.100 ms
> > > Throughput 1889.82 MB/sec  10 clients  10 procs  max_latency=0.154 ms
> > > Throughput 2406.57 MB/sec  20 clients  20 procs  max_latency=3.667 ms
> > > Throughput 2318.00 MB/sec  40 clients  40 procs  max_latency=0.390 ms
> > > Throughput 2384.85 MB/sec  80 clients  80 procs  max_latency=1.371 ms
> > >
> > >
> > > So what's going on here? I don't see anything exciting happening at the
> > > 40 mark. At the same time, I can't seem to reproduce Mike's latency pile
> > > up either :/
> >
> > Are you running tbench in the GUI so the per second output stimulates
> > assorted goo?  I'm using KDE fwtw.
>
> Nah, the IVB-EP is headless, doesn't even have systemd on, still running
> sysvinit.

Turns out load distribution on Yu's box wasn't going wonky way early
after all, so WA_WEIGHT's evil side is off topic wrt $subject.  Hohum.

	-Mike