linux-kernel - Very poor IO performance (high CPU load), libata

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-next>] [day] [month] [year] [list]

Message-ID: <20060715174555.GA27640@server.c-otto.de>
Date:	Sat, 15 Jul 2006 19:45:57 +0200
From:	Carsten Otto <c-otto@....de>
To:	linux-kernel@...r.kernel.org
Subject: Very poor IO performance (high CPU load), libata

Hello (again)!

System specs below.

My system sometimes[1] crashes in the sense that every HDD access is slow
as hell and most of both CPUs' power is used for IO waiting. Then "top"
shows more than 80% "wa" and the corresponding counter in /proc/stat
increases a lot. When plotting these values with rrdtool I see up to 5%
IO wait with normal behaviour and peaks with up to 40% under heavy load.

In the problem case the IO wait never drops below 40% no matter how light
the HDD load is. Logging in into the system via SSH then takes more than
two minutes and other tasks are equally slow.

Disabling AHCI/ACPI/SMP in the kernel did not help.
I also tried several kernel versions including 2.6.16 to 2.6.18 (rc,
mm).

/proc/interrupts shows a lot of interrupts for my network cards, but
disabling the network does not solve the problem.

A reboot usually solves the problem for some time.

There might be a problem with my hardware (in a not yet determined
device) causing this problem. But as long as I do not know what is wrong
I still see the chance of a software error in the kernel.

System specs:
- Mainboard with Intel 945p and iCH7R (Foxconn 945P7AA-8EKRS2)
- Intel Pentium D 805 (Dual Core, 2.66 GHz, 1 MB cache each)
- 4x Maxtor MaXLine III (300GB, 16MB Cache, SATA2)

[1] Sometimes: More than daily, at the moment I am lucky and noticed no
problem for hours.

Thanks a lot,
-- 
Carsten Otto
c-otto@....de
www.c-otto.de

Download attachment "signature.asc" of type "application/pgp-signature" (190 bytes)