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From: Andrew Morton <akpm@osdl.org>
To: Phy Prabab <phyprabab@yahoo.com>
Cc: wli@holomorphy.com, jakob@unthought.net, linux-kernel@vger.kernel.org
Subject: Re: Help understanding slow down
Date: Mon, 24 May 2004 00:53:31 -0700	[thread overview]
Message-ID: <20040524005331.71465614.akpm@osdl.org> (raw)
In-Reply-To: <20040524063959.5107.qmail@web90007.mail.scd.yahoo.com>

Phy Prabab <phyprabab@yahoo.com> wrote:
>
> Okay, here is the output:
> 
>  317955 total                                     
>  0.1302
>  263633 poll_idle                               
>  4545.3966
>    6764 do_page_fault                             
>  5.1951
>    3650 kmap_atomic 

It's strange that you appear to be using poll_idle().  Maybe it's an error
in the profiler - it sometimes makes mistakes in identifying small
functions.

But if you _are_ using poll_idle() and if your CPU is hyperthreaded then
yes, one "CPU" is going to take a performance hit from the "idle" one.

Is your CPU hyperthreaded?  (cat /proc/cpuinfo)

Are you booting with "idle=poll"?  Do `dmesg -s 1000000 | grep idle'.


  parent reply	other threads:[~2004-05-24  7:54 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-24  0:32 Help understanding slow down Phy Prabab
2004-05-24  0:57 ` Phy Prabab
2004-05-24  1:04   ` William Lee Irwin III
2004-05-24  1:25     ` Jakob Oestergaard
2004-05-24  1:28       ` William Lee Irwin III
2004-05-24  1:51         ` Phy Prabab
2004-05-24  2:42           ` Nick Piggin
2004-05-24  2:43           ` Andrew Morton
2004-05-24  6:23             ` Phy Prabab
2004-05-24  6:27               ` William Lee Irwin III
2004-05-24  6:39                 ` Phy Prabab
2004-05-24  7:21                   ` Phy Prabab
2004-05-24  7:44                     ` Nick Piggin
2004-05-24  7:50                       ` Phy Prabab
2004-05-24  7:59                         ` Nick Piggin
2004-05-24 10:43                           ` Jakob Oestergaard
2004-05-24 14:13                     ` Martin J. Bligh
2004-05-24  7:53                   ` Andrew Morton [this message]
2004-05-24  8:00                     ` Phy Prabab
2004-05-25 10:32                     ` Ingo Molnar
2004-05-25  9:29                       ` Andrew Morton
2004-05-25 11:42                         ` Ingo Molnar
2004-05-25  9:58                           ` Andrew Morton
2004-05-25 12:25                             ` Ingo Molnar
2004-05-24  6:33   ` Paul Rolland
2004-05-24 17:28     ` Roger Luethi
  -- strict thread matches above, loose matches on Subject: below --
2004-05-24  1:37 Robert M. Stockmann
2004-05-24  1:50 ` Phy Prabab
2004-05-24  3:31 ` Robert M. Stockmann
2004-05-24  6:14   ` Phy Prabab
2004-05-24 18:36     ` Robert M. Stockmann

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