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From: arno@natisbad•org (Arnaud Ebalard)
To: Willy Tarreau <w@1wt•eu>
Cc: Eric Dumazet <eric.dumazet@gmail•com>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons•com>,
	Florian Fainelli <f.fainelli@gmail•com>,
	simon.guinot@sequanux•org, netdev@vger•kernel.org,
	edumazet@google•com, Cong Wang <xiyou.wangcong@gmail•com>,
	linux-arm-kernel@lists•infradead.org
Subject: Re: [BUG,REGRESSION?] 3.11.6+,3.12: GbE iface rate drops to few KB/s
Date: Wed, 20 Nov 2013 20:26:16 +0100	[thread overview]
Message-ID: <87zjoyoox3.fsf@natisbad.org> (raw)
In-Reply-To: <20131120191145.GP8581@1wt.eu> (Willy Tarreau's message of "Wed, 20 Nov 2013 20:11:45 +0100")

Hi,

Willy Tarreau <w@1wt•eu> writes:

> first, thanks for all these tests.
>
> On Wed, Nov 20, 2013 at 12:53:43AM +0100, Arnaud Ebalard wrote:
> (...)
>> In the end, here are the conclusions *I* draw from this test session,
>> do not hesitate to correct me:
>> 
>>  - Eric, it seems something changed in linus tree betwen the beginning
>>    of the thread and now, which somehow reduces the effect of the
>>    regression we were seen: I never got back the 256KB/s.
>>  - You revert patch still improves the perf a lot
>>  - It seems reducing MVNETA_TX_DONE_TIMER_PERIOD does not help
>>  - w/ your revert patch, I can confirm that mvneta driver is capable of
>>    doing line rate w/ proper tweak of TCP send window (256KB instead of
>>    4M)
>>  - It seems I will I have to spend some time on the SATA issues I
>>    previously thought were an artefact of not cleaning my tree during a
>>    debug session [1], i.e. there is IMHO an issue.
>
> Could you please try Eric's patch that was just merged into Linus' tree
> if it was not yet in the kernel you tried :
>
>   98e09386c0e  tcp: tsq: restore minimal amount of queueing

I have it in my quilt set.


> For me it restored the original performance (I saturate the Gbps with
> about 7 concurrent streams).
>
> Further, I wrote the small patch below for mvneta. I'm not sure it's
> smp-safe but it's a PoC. In mvneta_poll() which currently is only called
> upon Rx interrupt, it tries to flush all possible remaining Tx descriptors
> if any. That significantly improved my transfer rate, now I easily achieve
> 1 Gbps using a single TCP stream on the mirabox. Not tried on the AX3 yet.
>
> It also increased the overall connection rate by 10% on empty HTTP responses
> (small packets), very likely by reducing the dead time between some segments!
>
> You'll probably want to give it a try, so here it comes.

hehe, I was falling short of patches to test tonight ;-) I will give it
a try now.

Cheers,

a+

  reply	other threads:[~2013-11-20 19:26 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-10 13:53 [BUG,REGRESSION?] 3.11.6+,3.12: GbE iface rate drops to few KB/s Arnaud Ebalard
2013-11-12  6:48 ` Cong Wang
2013-11-12  7:56   ` Arnaud Ebalard
2013-11-12  8:36     ` Willy Tarreau
2013-11-12  9:14       ` Arnaud Ebalard
2013-11-12 10:01         ` Willy Tarreau
2013-11-12 15:34           ` Arnaud Ebalard
2013-11-13  7:22             ` Willy Tarreau
2013-11-17 14:19               ` Willy Tarreau
2013-11-17 17:41                 ` Eric Dumazet
2013-11-19  6:44                   ` Arnaud Ebalard
2013-11-19 13:53                     ` Eric Dumazet
2013-11-19 17:43                       ` Willy Tarreau
2013-11-19 18:31                         ` Eric Dumazet
2013-11-19 18:41                           ` Willy Tarreau
2013-11-19 23:53                             ` Arnaud Ebalard
2013-11-20  0:08                               ` Eric Dumazet
2013-11-20  0:35                                 ` Willy Tarreau
2013-11-20  0:43                                   ` Eric Dumazet
2013-11-20  0:52                                     ` Willy Tarreau
2013-11-20  8:50                               ` Thomas Petazzoni
2013-11-20 19:11                               ` Willy Tarreau
2013-11-20 19:26                                 ` Arnaud Ebalard [this message]
2013-11-20 21:28                                 ` Arnaud Ebalard
2013-11-20 21:54                                   ` Willy Tarreau
2013-11-21  0:44                                     ` Willy Tarreau
2013-11-21 18:38                                       ` ARM network performance and dma_mask (was: [BUG,REGRESSION?] 3.11.6+,3.12: GbE iface rate drops to few KB/s) Willy Tarreau
2013-11-21 19:04                                         ` Thomas Petazzoni
2013-11-21 21:51                                           ` Willy Tarreau
2013-11-21 22:01                                         ` ARM network performance and dma_mask Rob Herring
2013-11-21 22:13                                           ` Willy Tarreau
2013-11-21 21:51                                       ` [BUG,REGRESSION?] 3.11.6+,3.12: GbE iface rate drops to few KB/s Arnaud Ebalard
2013-11-21 21:52                                         ` Willy Tarreau
2013-11-21 22:00                                           ` Eric Dumazet
2013-11-21 22:55                                             ` Arnaud Ebalard
2013-11-21 23:23                                               ` Rick Jones
2013-11-20 17:12                   ` Willy Tarreau
2013-11-20 17:30                     ` Eric Dumazet
2013-11-20 17:38                       ` Willy Tarreau
2013-11-20 18:52                       ` David Miller
2013-11-20 17:34                     ` Willy Tarreau
2013-11-20 17:40                       ` Eric Dumazet
2013-11-20 18:15                         ` Willy Tarreau
2013-11-20 18:21                           ` Eric Dumazet
2013-11-20 18:29                             ` Willy Tarreau
2013-11-20 19:22                           ` Arnaud Ebalard
2013-11-18 10:09                 ` David Laight
2013-11-18 10:52                   ` Willy Tarreau
2013-11-18 10:26                 ` Thomas Petazzoni
2013-11-18 10:44                   ` Simon Guinot
2013-11-18 16:54                     ` Stephen Hemminger
2013-11-18 17:13                       ` Eric Dumazet
2013-11-18 10:51                   ` Willy Tarreau
2013-11-18 17:58                     ` Florian Fainelli
2013-11-12 14:39     ` [PATCH] tcp: tsq: restore minimal amount of queueing Eric Dumazet
2013-11-12 15:24       ` Sujith Manoharan
2013-11-13 14:06       ` Eric Dumazet
2013-11-13 14:32       ` [PATCH v2] " Eric Dumazet
2013-11-13 21:18         ` Arnaud Ebalard
2013-11-13 21:59           ` Holger Hoffstaette
2013-11-13 23:40             ` Eric Dumazet
2013-11-13 23:52               ` Holger Hoffstaette
2013-11-17 23:15                 ` Francois Romieu
2013-11-18 16:26                   ` Holger Hoffstätte
2013-11-18 16:47                     ` Eric Dumazet
2013-11-13 22:41           ` Eric Dumazet
2013-11-14 21:26         ` David Miller

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