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From: Tejun Heo <tj@kernel.org>
To: Deepawali Verma <dverma249@gmail.com>
Cc: Chinmay V S <cvs268@gmail.com>,
	Daniel Taylor <Daniel.Taylor@wdc.com>,
	anish singh <anish198519851985@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Work queue questions
Date: Mon, 24 Sep 2012 13:08:09 -0700	[thread overview]
Message-ID: <20120924200809.GC29689@google.com> (raw)
In-Reply-To: <CAHCeSFr4stF6BNGL7=7oPYzKqOZ-Ya8VUD02rjFRq1thMULFXw@mail.gmail.com>

Hello,

On Mon, Sep 24, 2012 at 08:57:40PM +0100, Deepawali Verma wrote:
> May be I misunderstood, I read in the documentation about max_active.
> In this case, max_active is 1, but I created three workqueues, do you

I see.  Why are you doing that?  Is there ordering requirement?  Why
not just use system_unbound_wq?

> mean to say for this case, single thread can process three requests
> queued up in the three different workqueues.

In the following execution log you posted,

  kworker/u:1-21    [000]   110.964895: task_event: MYTASKJOB2381 XStarted
  kworker/u:1-21    [000]   110.964909: task_event: MYTASKJOB2381 Xstopped
  kworker/u:1-21    [000]   110.965137: task_event: MYTASKJOB2382 XStarted
  kworker/u:1-21    [000]   110.965154: task_event: MYTASKJOB2382 Xstopped
  kworker/u:5-3724  [000]   110.965311: task_event: MYTASKJOB2383 XStarted
  kworker/u:5-3724  [000]   110.965325: task_event: MYTASKJOB2383 Xstopped

The first two got executed on the same worker thread but the third one
is on a different one.  It really looks like you just don't have large
enough work for scheduler to interleave them or migrate workers to
different CPUs.

Thanks.

-- 
tejun

  reply	other threads:[~2012-09-24 20:08 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-21 17:35 Work queue questions Dinky Verma
2012-09-21 17:49 ` Tejun Heo
2012-09-21 18:30   ` Deepawali Verma
2012-09-21 18:35     ` Tejun Heo
2012-09-21 19:26       ` Deepawali Verma
2012-09-21 19:27         ` Tejun Heo
2012-09-21 19:35           ` Deepawali Verma
2012-09-21 19:40             ` Tejun Heo
2012-09-22  4:24             ` anish singh
2012-09-22  5:27               ` Daniel Taylor
2012-09-22  6:05                 ` anish singh
2012-09-22  6:12                   ` Tejun Heo
2012-09-22  6:18                   ` Daniel Taylor
2012-09-24  7:25                     ` Deepawali Verma
     [not found]                       ` <CAK-9PRB7KvPNgcsXiNG08-7OdrkkNc2ushusXh9rVm93J0xcHA@mail.gmail.com>
     [not found]                         ` <CAHCeSFqmeOkKySxMUXgtnev+HL-NC6MdmeuDYONymYaNczb7RA@mail.gmail.com>
2012-09-24 16:56                           ` Deepawali Verma
2012-09-24 18:10                             ` Tejun Heo
2012-09-24 19:57                               ` Deepawali Verma
2012-09-24 20:08                                 ` Tejun Heo [this message]
2012-09-24 20:52                                   ` Deepawali Verma
2012-09-24 20:54                                     ` Tejun Heo
2012-09-25  3:05                                   ` anish singh
2012-09-24 17:07                           ` Chinmay V S

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