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From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	David Miller <davem@davemloft.net>,
	Rik van Riel <riel@redhat.com>, Paolo Abeni <pabeni@redhat.com>,
	Hannes Frederic Sowa <hannes@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	brouer@redhat.com
Subject: Re: [PATCH] softirq: let ksoftirqd do its job
Date: Fri, 2 Sep 2016 10:35:34 +0200	[thread overview]
Message-ID: <20160902103534.670b8f6a@redhat.com> (raw)
In-Reply-To: <20160901152802.GV10153@twins.programming.kicks-ass.net>

On Thu, 1 Sep 2016 17:28:02 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Sep 01, 2016 at 03:30:42PM +0200, Jesper Dangaard Brouer wrote:
> > Still... enabled!
> > Hmmm.. more idea how to disable this???  
> 
> I think you ought to be able to assign yourself to the root cgroup,
> something like:
> 
>   echo $$ > /cgroup/tasks
> 
> or wheverever the cpu-cgroup controller is mounted at.
> 
> But its been a fair while since I touched any of that, its not a CONFIG
> I have enabled much.

I could not figure out how to disable autogroups, so I ended up
compiling the kernel without CONFIG_SCHED_AUTOGROUP.

  PID   PR   S  %CPU     TIME+ 	COMMAND
    3   20   R  20.7   0:53.05 	ksoftirqd/0
 9299   20   R  16.3   0:03.62 	udp_sink
 9296   20   S  16.0   0:03.59 	udp_sink
 9297   20   R  16.0   0:03.58 	udp_sink
 9298   20   R  16.0   0:03.57 	udp_sink
 9295   20   R  15.3   0:03.43 	udp_sink

Top new shows the CPU distribution is more correct, thus we can
concluded the artifact I saw was indeed caused by autogroup.

I can also confirm that my netperf UDP_STREAM tests now work again,
but I need around 32 parallel netperf to counter the effectiveness of
the ksoftirqd process.  While I only need 5 udp_sink programs.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

  reply	other threads:[~2016-09-02  8:35 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4f1c4b38528762619fff1fa963de8971006c1234.1472460085.git.pabeni@redhat.com>
     [not found] ` <20160831100854.23dad2d8@redhat.com>
     [not found]   ` <1472650472.14381.317.camel@edumazet-glaptop3.roam.corp.google.com>
     [not found]     ` <1472650688.32433.115.camel@redhat.com>
     [not found]       ` <1472652643.14381.320.camel@edumazet-glaptop3.roam.corp.google.com>
     [not found]         ` <20160831164216.2901190c@redhat.com>
     [not found]           ` <1472661956.14381.335.camel@edumazet-glaptop3.roam.corp.google.com>
2016-08-31 17:42             ` [PATCH] softirq: let ksoftirqd do its job Eric Dumazet
2016-08-31 19:40               ` Jesper Dangaard Brouer
2016-08-31 20:42                 ` Eric Dumazet
2016-08-31 21:51                   ` Jesper Dangaard Brouer
2016-08-31 22:27                     ` Eric Dumazet
2016-08-31 22:47                       ` Rick Jones
2016-08-31 23:11                         ` Eric Dumazet
2016-08-31 23:29                           ` Rick Jones
2016-09-01 10:38                             ` Jesper Dangaard Brouer
2016-09-01 13:06                               ` Eric Dumazet
2016-09-01 11:02                     ` Jesper Dangaard Brouer
2016-09-01 11:11                       ` Hannes Frederic Sowa
2016-09-01 11:53                       ` Peter Zijlstra
2016-09-01 12:29                         ` Jesper Dangaard Brouer
2016-09-01 12:38                           ` Jesper Dangaard Brouer
2016-09-01 12:48                             ` Peter Zijlstra
2016-09-01 13:30                               ` Jesper Dangaard Brouer
2016-09-01 15:28                                 ` Peter Zijlstra
2016-09-02  8:35                                   ` Jesper Dangaard Brouer [this message]
2016-09-01 12:57                             ` Eric Dumazet
2016-09-01 13:00                               ` Hannes Frederic Sowa
2016-09-01 13:25                                 ` Eric Dumazet
2016-09-01 12:05                   ` Hannes Frederic Sowa
2016-09-01 12:51                     ` Eric Dumazet
2016-09-01 12:01               ` Hannes Frederic Sowa
2016-09-02  6:39               ` David Miller
2016-09-23 11:35                 ` Daniel Borkmann
2016-09-23 11:53                   ` Peter Zijlstra
2016-09-23 16:51                     ` Jesper Dangaard Brouer
2016-09-23 21:16                       ` Peter Zijlstra
2016-09-30 11:55               ` [tip:irq/core] softirq: Let " tip-bot for Eric Dumazet

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