From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: Mikael Johansson <mpjohans@pcu.helsinki.fi>
Cc: linux-raid@vger.kernel.org, <linux-kernel@vger.kernel.org>
Subject: Re: RAID-0 read perf. decrease after 2.4.20
Date: Fri, 21 Nov 2003 11:47:49 -0200 (BRST) [thread overview]
Message-ID: <Pine.LNX.4.44.0311211144130.15440-100000@logos.cnet> (raw)
In-Reply-To: <Pine.OSF.4.58.0311201827090.515286@soul.helsinki.fi>
On Thu, 20 Nov 2003, Mikael Johansson wrote:
>
> Hello All!
>
> Has anyone else experienced a drastic drop in read performance on software
> RAID-0 with post 2.4.20 kernels? We have a few Athlon XP's here at our
> lab with double IDE disks on different channels set up as RAID-0. Some
> bonnie++ benchmark results with various kernels, on the same machine
> (Athlon XP 2400+, 2 GHz, 1.5 GB RAM, VIA chipset, 2*Maxtor 120 GB
> 6Y060L0):
> write read
> 2.4.20-ac1: 88,000 135,000 K/sec
> 2.4.21-pre7: 93,000 75,000
> 2.4.22-ac4: 94,000 82,000
>
> So the write speed has gone up a bit, but the read speed performance has
> plunged. Any ideas on what happened between 2.4.20 and 2.4.21 and what to
> do about it? I'm eagerly awaiting suggestions, good read speed is quite
> critical for many of our calculations :-) I will of course provide more
> details if necessary.
There have been no significant changes in the RAID driver in 2.4.21, so I
suspect the cause for the slowdowns might the changes to the IO scheduler
(ll_rw_blk.c) or VM changes.
Isolating the -pre which the slowdown starts helps a lot.
next prev parent reply other threads:[~2003-11-21 13:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-20 16:45 RAID-0 read perf. decrease after 2.4.20 Mikael Johansson
2003-11-21 13:47 ` Marcelo Tosatti [this message]
2003-11-21 19:56 ` Mikael Johansson
2003-12-08 12:47 ` Marcelo Tosatti
2003-12-08 13:11 ` Marc-Christian Petersen
2003-12-08 13:21 ` Marcelo Tosatti
2003-11-24 10:05 Martin Knoblauch
2003-11-25 5:01 ` Joshua Schmidlkofer
2003-11-25 9:41 Martin Knoblauch
2003-12-16 12:51 Martin Knoblauch
2003-12-18 13:41 ` Marcelo Tosatti
2003-12-18 14:37 ` Martin Knoblauch
2004-07-04 23:28 ` Mikael Johansson
2003-12-18 19:13 ` Mike Fedyk
2003-12-18 19:17 ` Marcelo Tosatti
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