Re: poor sata performance on 2.6

Konstantin Sobolev
2004-04-15T14:45:28Z

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?

/KoS
* I haven't lost my mind...It's backed up somewhere!