Re: Performance drop in Linux 2.4.19-XFS 1.2 ?

[Seth Mos <knuffie@xxxxxxxxx>]

At 10:04 30-7-2003 -0700, Cliff Wells wrote:
> On Wed, 2003-07-30 at 02:09, Seth Mos wrote:
> > At 18:31 29-7-2003 -0700, Ravi Wijayaratne wrote:
> > >Hi,
> > >
> > >We are seeing a %15 performance drop when we move from XFS 1.1 to 1.2.
> > >Here are some of our particulars:
> > >We have been testing the performance of Linux-2.4.19 and XFS 1.2 with
> > >NetBench.
> > >We compared the performance with that of Linux-2.4.18 and XFS 1.1.
> > >We have been running Samba 3.0.
> >
> > The only problem I know of which is not exclusive to XFS (ext3 does 
> this as
> > well) is one on the read performance of 2.4.18 vs the 2.4.20 errata kernel.
> >
> > On 2.4.18-27 I get 170MB/sec read speed
> > on 2.4.20-18 I get 80MB/sec read speed.
> >
> > the write speed stays consistent between these releases but the enormous
> > drop in read speed is very strange. It appears to be present in the
> > standard rh errata as well.
>
> Try hdparm -a 512 /dev/hdx
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=105830842018800&w=2

That's IDE. I am talking about scsi. The 3ware controller is just a scsi 
controller with IDE disks, but the OS doesn't know what disks are behind 
the raid container.

[root@lsnetniet root]# hdparm /dev/sda

/dev/sda:
 readonly     =  0 (off)
 geometry     = 45051/255/63, sectors = 723757824, start = 0
[root@lsnetniet root]# hdparm -tT /dev/sda

/dev/sda:
 Timing buffer-cache reads:   128 MB in  0.66 seconds =193.94 MB/sec
 Timing buffered disk reads:  64 MB in  1.06 seconds = 60.38 MB/sec
[root@lsnetniet root]# hdparm -a 512 /dev/sda

/dev/sda:
 setting fs readahead to 512
 BLKRASET failed: Invalid argument
 readahead    = 120 (on)
[root@lsnetniet root]# uname -a
Linux lsnetniet.coltex.nl 2.4.20-18-rh-xfs #2 SMP ma jun 23 11:01:51 CEST 
2003 i686 unknown
[root@lsnetniet root]#

And thus the experiment fails.

Any other suggestions :-)

Cheers

--
Seth
It might just be your lucky day, if you only knew.