From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Rutkov Denis <dendron2000@mail.ru>
Cc: linux-kernel@vger.kernel.org
Subject: Re: High kernel CPU usage when copying files
Date: Fri, 24 Apr 2009 11:23:48 +0100 [thread overview]
Message-ID: <20090424112348.64fb5c73@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <E1LxIDf-0004qD-00.dendron2000-mail-ru@f159.mail.ru>
> Whenever I copy files I got very high CPU usage from kernel. I tested this with ext3, ext4 and fat32 file systems. To trace the problem I installed oprofile and debug kernel image. I ran the profiler during file copying and saw that there are many calls to copy_to_user_ll and copy_from_user_ll functions. So I have two questions:
>
> 1. Is this normal I get so many of those function calls?
Yes
> 2. What can I do to further trace this bug?
Are you seeing high CPU usage or just a lot of D state processes (blocked
waiting I/O) ?
Alan
next prev parent reply other threads:[~2009-04-24 10:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-24 10:01 Rutkov Denis
2009-04-24 10:23 ` Alan Cox [this message]
2009-04-24 10:30 ` Re[2]: " Rutkov Denis
2009-04-24 14:21 ` Heinz Diehl
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