Subject: Re: [sctp] ef2820a735: -50% netperf Throughput_Mbps

From: Fengguang Wu <[email-masked]>
Date: Sun, 23 Feb 2014 09:37:39 +0800

Hi Matija,

On Wed, Feb 19, 2014 at 06:06:34PM +0100, Matija Glavinic Pecotic wrote:
> Hello Fengguang,
> 
> On 02/19/2014 02:20 PM, ext Fengguang Wu wrote:
> > Hi Matija,
> > 
> > We noticed the below changes on commit ef2820a735f74ea60335f8ba3801b844f0cb184d
> > (" net: sctp: Fix a_rwnd/rwnd management to reflect real state of the receiver's buffer")
> > in netperf SCTP_STREAM tests:
> 
> thanks for the info. Though, I've ran netperf in my environment, with and without patch, and I havent observed any difference.
> 
> Could you please give me information on your environment, how do you invoke netperf, and other details you think I might be interested in to observe problem by myself

I see the same regression on both T410 and NHM EX server. On each test
machine, I'm running (2*nr_logical_cpu) the below command in parallel:

        netperf -t SCTP_STREAM -c -C -l 120

Thanks,
Fengguang

> Thanks!
> 
> > cd0f0b95fd2cd2b  ef2820a735f74ea60335f8ba3  
> > ---------------  -------------------------  
> >          8 ~ 0%     -50.0%          4 ~ 0%  TOTAL netperf.Throughput_Mbps
> >      54287 ~44%    +338.1%     237842 ~48%  TOTAL cpuidle.C1E-NHM.time
> >   12008353 ~12%     -56.0%    5281848 ~ 0%  TOTAL proc-vmstat.pgalloc_normal
> >     114861 ~ 0%     -50.3%      57085 ~ 3%  TOTAL softirqs.NET_RX
> >   12964639 ~11%     -55.1%    5818663 ~ 0%  TOTAL proc-vmstat.pgfree
> >     866489 ~ 0%     -43.3%     491417 ~ 0%  TOTAL proc-vmstat.pgalloc_dma32
> >     119373 ~17%     -39.1%      72661 ~ 1%  TOTAL softirqs.SCHED
> >       1985 ~13%     -24.3%       1502 ~19%  TOTAL slabinfo.kmalloc-128.active_objs
> >       2139 ~20%     -28.4%       1532 ~ 4%  TOTAL proc-vmstat.nr_alloc_batch
> >     124360 ~33%     -31.0%      85748 ~ 2%  TOTAL softirqs.RCU
> >       1977 ~ 9%     -18.5%       1610 ~ 9%  TOTAL slabinfo.UDP.active_objs
> >       1977 ~ 9%     -18.5%       1610 ~ 9%  TOTAL slabinfo.UDP.num_objs
> >       2066 ~ 6%     -12.9%       1800 ~ 7%  TOTAL slabinfo.kmalloc-128.num_objs
> >       1738 ~10%     -18.4%       1418 ~ 9%  TOTAL slabinfo.UDPv6.active_objs
> >       1738 ~10%     -18.4%       1418 ~ 9%  TOTAL slabinfo.UDPv6.num_objs
> >        923 ~10%     -17.7%        760 ~ 8%  TOTAL slabinfo.TCPv6.active_objs
> >        923 ~10%     -17.7%        760 ~ 8%  TOTAL slabinfo.TCPv6.num_objs
> >        989 ~ 9%     -17.1%        820 ~ 7%  TOTAL slabinfo.TCP.active_objs
> >        989 ~ 9%     -17.1%        820 ~ 7%  TOTAL slabinfo.TCP.num_objs
> >     398761 ~44%     -32.6%     268792 ~ 3%  TOTAL numa-vmstat.node2.numa_hit
> >     389672 ~49%     -32.9%     261443 ~ 3%  TOTAL numa-vmstat.node0.numa_hit
> >        447 ~ 1%     -13.8%        385 ~ 0%  TOTAL vmstat.system.cs
> > 
> > Note: the "~ XX%" numbers are stddev percent.
> > 
> >                               netperf.Throughput_Mbps
> > 
> >      4 *+-*--*--*--*-*--*--*--*--*--*--*--*-*--*--*--*--*--*--*--*-*--*--*--*
> >        |                                                                    |
> >        |                                                                    |
> >    3.5 ++                                                                   |
> >        |                                                                    |
> >        |                                                                    |
> >        |                                                                    |
> >      3 ++                                                                   |
> >        |                                                                    |
> >        |                                                                    |
> >    2.5 ++                                                                   |
> >        |                                                                    |
> >        |                                                                    |
> >        |                                                                    |
> >      2 O+-O--O--O--O-O--O--O--O--O--O--O--O-O--O--O--O--O--O--O-------------+
> > 
> > 
> >                                  vmstat.system.cs
> > 
> >    460 ++------------------------*--*----------------*----------------------+
> >        |       .*..    .*..     :    +              +              *..     .*
> >    450 ++    *.     .*.    *..  :     +    .*..*.. +    *..*..*.. +     .*. |
> >    440 *+   :      *           :       *..*       *              *    *.    |
> >        |:   :                 *                                             |
> >    430 ++: :                                                                |
> >    420 ++: :                                                                |
> >        |  *                                                                 |
> >    410 ++                                                                   |
> >    400 ++                                                                   |
> >        |                                                                    |
> >    390 ++            O        O             O     O        O                |
> >    380 O+ O  O  O       O  O     O  O  O  O    O     O  O     O             |
> >        |           O                                                        |
> >    370 ++-------------------------------------------------------------------+
> >