From: Fengguang Wu <fengguang.wu@intel.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: -27% netperf TCP_STREAM regression by "tcp_memcontrol: Kill struct tcp_memcontrol"
Date: Wed, 23 Oct 2013 12:46:47 +0100 [thread overview]
Message-ID: <20131023114647.GA30252@localhost> (raw)
In-Reply-To: <87a9i0l3v1.fsf@xmission.com>
On Wed, Oct 23, 2013 at 02:43:14AM -0700, Eric W. Biederman wrote:
> Fengguang Wu <fengguang.wu@intel.com> writes:
>
> > On Tue, Oct 22, 2013 at 09:38:10PM -0700, Eric W. Biederman wrote:
> >> David Miller <davem@davemloft.net> writes:
> >>
> >> > From: fengguang.wu@intel.com
> >> > Date: Tue, 22 Oct 2013 22:41:29 +0100
> >> >
> >> >> We noticed big netperf throughput regressions
> >> >>
> >> >> a4fe34bf902b8f709c63 2e685cad57906e19add7
> >> >> ------------------------ ------------------------
> >> >> 707.40 -40.7% 419.60 lkp-nex04/micro/netperf/120s-200%-TCP_STREAM
> >> >> 2775.60 -23.7% 2116.40 lkp-sb03/micro/netperf/120s-200%-TCP_STREAM
> >> >> 3483.00 -27.2% 2536.00 TOTAL netperf.Throughput_Mbps
> >> >>
> >> >> and bisected it to
> >> >>
> >> >> commit 2e685cad57906e19add7189b5ff49dfb6aaa21d3
> >> >> Author: Eric W. Biederman <ebiederm@xmission.com>
> >> >> Date: Sat Oct 19 16:26:19 2013 -0700
> >> >>
> >> >> tcp_memcontrol: Kill struct tcp_memcontrol
> >> >
> >> > Eric please look into this, I'd rather have a fix to apply than revert your
> >> > work.
> >>
> >> Will do I expect some ordering changed, and that changed the cache line
> >> behavior.
> >>
> >> If I can't find anything we can revert this one particular patch without
> >> affecting anything else, but it would be nice to keep the data structure
> >> smaller.
> >>
> >> Fengguag what would I need to do to reproduce this?
> >
> > Eric, attached is the kernel config.
> >
> > We used these commands in the test:
> >
> > netserver
> > netperf -t TCP_STREAM -c -C -l 120 # repeat 64 times and get average
Sorry it's not about repeating, but running 64 netperf in parallel.
The number 64 is 2 times the number of logical CPUs.
> > btw, we've got more complete change set (attached) and also noticed
> > performance increase in the TCP_SENDFILE case:
> >
> > a4fe34bf902b8f709c63 2e685cad57906e19add7
> > ------------------------ ------------------------
> > 707.40 -40.7% 419.60 lkp-nex04/micro/netperf/120s-200%-TCP_STREAM
> > 2572.20 -17.7% 2116.20 lkp-sb03/micro/netperf/120s-200%-TCP_MAERTS
> > 2775.60 -23.7% 2116.40 lkp-sb03/micro/netperf/120s-200%-TCP_STREAM
> > 1006.60 -54.4% 459.40 lkp-sbx04/micro/netperf/120s-200%-TCP_STREAM
> > 3278.60 -25.2% 2453.80 lkp-t410/micro/netperf/120s-200%-TCP_MAERTS
> > 1902.80 +21.7% 2315.00 lkp-t410/micro/netperf/120s-200%-TCP_SENDFILE
> > 3345.40 -26.7% 2451.00 lkp-t410/micro/netperf/120s-200%-TCP_STREAM
> > 15588.60 -20.9% 12331.40 TOTAL netperf.Throughput_Mbps
>
> I have a second question. Do you mount the cgroup filesystem? Do you
> set memory.kmem.tcp.limit_in_bytes?
No I didn't mount cgroup at all.
> If you aren't setting any memory cgroup limits or creating any groups
> this change should not have had any effect whatsoever. And you haven't
> mentioned it so I don't expect you are enabling the memory cgroup limits
> explicitly.
>
> If you have enabled the memory cgroups can you please describe your
> configuration as that may play a significant role.
>
> Eric
next prev parent reply other threads:[~2013-10-23 11:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-22 21:41 -27% netperf TCP_STREAM regression by "tcp_memcontrol: Kill struct tcp_memcontrol" fengguang.wu
2013-10-22 22:00 ` David Miller
2013-10-23 4:38 ` Eric W. Biederman
2013-10-23 6:10 ` Fengguang Wu
2013-10-23 9:43 ` Eric W. Biederman
2013-10-23 11:46 ` Fengguang Wu [this message]
2013-10-23 12:25 ` Christoph Paasch
2013-10-23 13:02 ` Eric Dumazet
2013-10-23 19:55 ` [PATCH] Fix: Dereference pointer-value of sk_prot->memory_pressure Eric W. Biederman
2013-10-23 20:15 ` David Miller
2013-10-23 19:58 ` Eric W. Biederman
2013-10-23 22:07 ` -27% netperf TCP_STREAM regression by "tcp_memcontrol: Kill struct tcp_memcontrol" Fengguang Wu
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