Re: [LKP] [rcu] c0f489d2c6f: -1.5% netperf.Throughput_tps

From: Mike Galbraith
Date: Fri Jul 25 2014 - 05:44:29 EST


On Fri, 2014-07-25 at 16:05 +0800, Aaron Lu wrote:
> On 07/25/2014 03:35 PM, Mike Galbraith wrote:
> > On Fri, 2014-07-25 at 14:45 +0800, Aaron Lu wrote:
> >> FYI, we noticed the below changes on
> >>
> >> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> >> commit c0f489d2c6fec8994c642c2ec925eb858727dc7b ("rcu: Bind grace-period kthreads to non-NO_HZ_FULL CPUs")
> >>
> >> abaa93d9e1de2c2 c0f489d2c6fec8994c642c2ec
> >> --------------- -------------------------
> >> 12654 ~ 0% -1.5% 12470 ~ 0% ivb43/netperf/300s-25%-TCP_CRR
> >> 12654 ~ 0% -1.5% 12470 ~ 0% TOTAL netperf.Throughput_tps
> >
> > Out of curiosity, what parameters do you use for this test? In my
>
> The cmdline for this test is:
> netperf -t TCP_CRR -c -C -l 300

Thanks. That doesn't switch as heftily as plain TCP_RR, but I'd still
expect memory layout etc to make bisection frustrating as heck. But no
matter, I was just curious.

Aside: running unbound, the load may get beaten up pretty bad by nohz if
it's enabled. Maybe for testing the network stack it'd be better to
remove that variable? Dunno, just a thought. I only mention it because
your numbers look very low unless the box is ancient or CPU is dinky.

-Mike

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