linux-kernel - Re: High kernel CPU usage when copying files

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090424112348.64fb5c73@lxorguk.ukuu.org.uk>
Date:	Fri, 24 Apr 2009 11:23:48 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Rutkov Denis <dendron2000@...l.ru>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: High kernel CPU usage when copying files

> 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/