From: Dimitrios Apostolou <jimis@gmx.net>
To: =?utf-8?q?Rafa=C5=82_Bilski?= <rafalbilski@interia.pl>
Subject: Re: high system cpu load during intense disk i/o
Date: Tue, 7 Aug 2007 12:43:51 +0300
User-Agent: KMail/1.9.7
Cc: linux-kernel@vger.kernel.org
References: <200708031903.10063.jimis@gmx.net> <46B7C18E.1050008@gmx.net> <46B83560.2060107@interia.pl>
In-Reply-To: <46B83560.2060107@interia.pl>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="utf-8"
Content-Transfer-Encoding: 8BIT
Content-Disposition: inline
Message-Id: <200708071243.52430.jimis@gmx.net>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1581
Lines: 38

On Tuesday 07 August 2007 12:03:28 Rafał Bilski wrote:
> >> Just tested (plain curiosity).
> >> via82cxxx average result @533MHz:
> >> /dev/hda:
> >> Timing cached reads:   232 MB in  2.00 seconds = 115.93 MB/sec
> >> Timing buffered disk reads:   64 MB in  3.12 seconds =  20.54 MB/sec
> >> pata_via average result @533MHz:
> >> /dev/sda:
> >> Timing cached reads:   234 MB in  2.01 seconds = 116.27 MB/sec
> >> Timing buffered disk reads:   82 MB in  3.05 seconds =  26.92 MB/sec
> >
> > Interesting! I haven't tried libata myself on that system, I only have
> > remote access to it so I'm a bit afraid...
>
> Just change root=/dev/hda1 to append="root=/dev/sda1" in lilo.conf.
> And change fstab. If You don't change "/" then system will go into single
> user mode after reboot.
>
> > Rafal, I hope that system you run hdparm on isn't the archlinux one! Is
> > it easy to load an old kernel (even two years old) and do the same test?
> > If it is, please let me know of the results.
>
> I don't think it is possible. If I remember right kernel can't be older
> then glibc kernel headers.
> Btw. My disk is 20GB 2,5" ATA33. I wonder how 26MB/s is possible. I don't
> expect more.

Aha! So perhaps libata gives even greater performance benefit for better 
drives. I'll try to get local access to my PC and try it. Thanks. 


Dimitris

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