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Re: Performance drop in Linux 2.4.19-XFS 1.2 ?

To: Nathan Scott <nathans@xxxxxxx>
Subject: Re: Performance drop in Linux 2.4.19-XFS 1.2 ?
From: Ravi Wijayaratne <ravi_wija@xxxxxxxxx>
Date: Tue, 29 Jul 2003 19:21:48 -0700 (PDT)
Cc: linux-xfs@xxxxxxxxxxx
In-reply-to: <20030730015854.GB770@frodo>
Sender: linux-xfs-bounce@xxxxxxxxxxx
Hi Nathan

Thank you for responding.

Log version:
-------------
We changing from v1 to v2 with the same parameters did not change 
the throughput.

Size of the Log:
----------------

I changed the size of the log from 64k to 256k for version 2 and
did not see a difference in performance. I beleive version 1 logs
support only 32k max internal logs. Is that correct ?

sunit values for logs/data:
---------------------------

I have not tried to tune these values yet. We set it to 64k
because our RAID chunk size was 64k. I will change the values
and see whethet performance changes significatly

Thanks
Ravi
 
--- Nathan Scott <nathans@xxxxxxx> wrote:
> On Tue, Jul 29, 2003 at 06:31:03PM -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 following are the configuration settings:
> > 
> > RAID config 0 or 5: 4 drives with chunk size of 64
> > 
> > xfs_info.sh /hd/vol_mnt0/
> > meta-data=/hd/vol_mnt0           isize=2048   agcount=74, agsize=1048560 
> > blks
> > data     =                       bsize=4096   blocks=76644352, imaxpct=25
> >          =                       sunit=16     swidth=16 blks, unwritten=0
> > naming   =version 2              bsize=4096  
> > log      =internal               bsize=4096   blocks=9360 version=2
> >          =                       sunit=16 blks
> > realtime =none                   extsz=65536  blocks=0, rtextents=0
> > 
> > We are running software RAID 0 and 5 (md). The performance numbers were 
> > obtained after the
> > RAID sync was completed.
> > 
> > For Linux 2.4.18-XFS-1.1 case we used log version 1.  
> > For Linux 2.4.19-XFS-1.2 case we used log version 2.
> > 
> > At mount time we changed the internal log size from 64k-256k, but that 
> > change did
> > not show any difference.
> > 
> 
> Try changing one thing at a time to try figure out what actually
> causes the performance changes.  ie. is it the change from 2.4.18
> to 2.4.19, or 1.1 to 1.2 XFS code, or is it the use of v1 vs. v2
> logs, or is it the use of larger iclogs, or the use of a large log
> sunit, or...  just too many variables here.
> 
> Posting the results of the benchmarks would be of use too.
> 
> thanks.
> 
> -- 
> Nathan


=====
------------------------------
Ravi Wijayaratne

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