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Date:   Mon, 1 May 2023 20:49:20 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mike Galbraith <efault@gmx.de>
Cc:     Chen Yu <yu.c.chen@intel.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Tim Chen <tim.c.chen@intel.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Abel Wu <wuyun.abel@bytedance.com>,
        Yicong Yang <yangyicong@hisilicon.com>,
        "Gautham R . Shenoy" <gautham.shenoy@amd.com>,
        Honglei Wang <wanghonglei@didichuxing.com>,
        Len Brown <len.brown@intel.com>,
        Chen Yu <yu.chen.surf@gmail.com>,
        Tianchen Ding <dtcccc@linux.alibaba.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Josh Don <joshdon@google.com>,
        kernel test robot <yujie.liu@intel.com>,
        Arjan Van De Ven <arjan.van.de.ven@intel.com>,
        Aaron Lu <aaron.lu@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 2/2] sched/fair: Introduce SIS_CURRENT to wake up
 short task on current CPU
Message-ID: <20230501184920.GC1597476@hirez.programming.kicks-ass.net>
References: <cover.1682661027.git.yu.c.chen@intel.com>
 <4081178486e025c89dbb7cc0e62bbfab95fc794a.1682661027.git.yu.c.chen@intel.com>
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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.