Re: poor sata performance on 2.6

[Denis Vlasenko]

On Thursday 15 April 2004 17:48, Konstantin Sobolev wrote:
> On Thursday 15 April 2004 18:33, Justin Cormack wrote:
> > On Thu, 2004-04-15 at 15:26, Konstantin Sobolev wrote:
> > > On Thursday 15 April 2004 18:00, Justin Cormack wrote:
> > > > hmm, odd. I get 50MB/s or so from normal (7200, 8MB cache) WD disks,
> > > > and Seagate from the same controller. Can you send lspci,
> > > > /proc/interrupts and dmesg...
> > >
> > > Attached are files for 2.6.5-mm5 with highmem, ACPI and APIC turned
> > > off.
> >
> > ah. Make a filesystem on it and mount it and try again. I see you have
> > no partition table and so probably no filesystem. This means the block
> > size is set to default 512byte not 4k which makes disk operations slow.
> > Any filesystem should default to block size of 4k, eg ext2.
>
> Very interesting!
> created partition table,
> kos sata # mkfs.ext2 /dev/sda1
> [..skipped..]
> kos mnt # cd /
> kos / # mkdir wd
> kos / # mount /dev/sda1 /wd
> kos / # hdparm -t -a8192 /dev/sda
>
> /dev/sda:
>  setting fs readahead to 8192
>  readahead    = 8192 (on)
>  Timing buffered disk reads:   82 MB in  3.03 seconds =  27.02 MB/sec
>
> kos / # mount | grep sda
> /dev/sda1 on /wd type ext2 (rw)
> kos / # hdparm -t -a8192 /dev/sda
>
> /dev/sda:
>  setting fs readahead to 8192
>  readahead    = 8192 (on)
>  Timing buffered disk reads:  206 MB in  3.02 seconds =  68.15 MB/sec
> kos / # hdparm -t -a8192 /dev/sda
>
> /dev/sda:
>  setting fs readahead to 8192
>  readahead    = 8192 (on)
>  Timing buffered disk reads:  206 MB in  3.02 seconds =  68.18 MB/sec
>
> So first time it gave the same loosy 27 MB/s and subsequent tests give
> pretty good 68 MB/s! Why?

Time to CC ide/libata/block layer folks

Jeff Garzik <jgarzik@xxxxxxxxx>
	libata man

IDE DRIVER [GENERAL]
P:      Bartlomiej Zolnierkiewicz
M:      B.Zolnierkiewicz@xxxxxxxxxxxxxx
L:      linux-kernel@xxxxxxxxxxxxxxx
L:      linux-ide@xxxxxxxxxxxxxxx
S:      Maintained

BLOCK LAYER
P:      Jens Axboe
M:      axboe@xxxxxxx
L:      linux-kernel@xxxxxxxxxxxxxxx
S:      Maintained

SIS 5513 IDE CONTROLLER DRIVER
P:      Lionel Bouton
M:      Lionel.Bouton@xxxxxxxx
W:      http://inet6.dyn.dhs.org/sponsoring/sis5513/index.html
W:      http://gyver.homeip.net/sis5513/index.html
S:      Maintained

--
vda

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