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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ben Greear <greearb@candelatech.com>, netdev <netdev@vger.kernel.org>
Subject: Re: TCP many-connection regression between 4.7 and 4.13 kernels.
Date: Mon, 22 Jan 2018 10:16:06 -0800	[thread overview]
Message-ID: <1516644966.3478.10.camel@gmail.com> (raw)
In-Reply-To: <e44000ce-1b94-f014-59c5-07305714ffcc@candelatech.com>

On Mon, 2018-01-22 at 09:28 -0800, Ben Greear wrote:
> My test case is to have 6 processes each create 5000 TCP IPv4 connections to each other
> on a system with 16GB RAM and send slow-speed data.  This works fine on a 4.7 kernel, but
> will not work at all on a 4.13.  The 4.13 first complains about running out of tcp memory,
> but even after forcing those values higher, the max connections we can get is around 15k.
> 
> Both kernels have my out-of-tree patches applied, so it is possible it is my fault
> at this point.
> 
> Any suggestions as to what this might be caused by, or if it is fixed in more recent kernels?
> 
> I will start bisecting in the meantime...
> 

Hi Ben

Unfortunately I have no idea.

Are you using loopback flows, or have I misunderstood you ?

How loopback connections can be slow-speed ?

  reply	other threads:[~2018-01-22 18:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-22 17:28 TCP many-connection regression between 4.7 and 4.13 kernels Ben Greear
2018-01-22 18:16 ` Eric Dumazet [this message]
2018-01-22 18:27   ` Willy Tarreau
2018-01-22 18:30   ` Ben Greear
2018-01-22 18:44     ` Ben Greear
2018-01-22 18:46     ` Josh Hunt
2018-01-23 22:06       ` Ben Greear
2018-01-23 21:49   ` TCP many-connection regression (bisected to 4.5.0-rc2+) Ben Greear
2018-01-23 22:07     ` Eric Dumazet
2018-01-23 22:09       ` Ben Greear
2018-01-23 22:29         ` Eric Dumazet
2018-01-23 23:10           ` Ben Greear
2018-01-23 23:21             ` Eric Dumazet
2018-01-23 23:27               ` Ben Greear
2018-01-24  0:05                 ` Ben Greear

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