From: Martin Knoblauch <knobi@knobisoft.de>
To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: RAID-0 read perf. decrease after 2.4.20
Date: Thu, 18 Dec 2003 06:37:41 -0800 (PST) [thread overview]
Message-ID: <20031218143741.25747.qmail@web13908.mail.yahoo.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0312181140540.4547-100000@logos.cnet>
--- Marcelo Tosatti <marcelo.tosatti@cyclades.com> wrote:
>
>
> On Tue, 16 Dec 2003, Martin Knoblauch wrote:
>
> > On Monday 08 December 2003 13:47, Marcelo Tosatti wrote:
> >
> > Hi Marcelo,
> >
> > > 2.4.20-aa included rmap and some VM modifications most notably
> > > "drop_behind()" logic which I believe should be the reason for
> the
> > huge
> > > read speedups. Can you please try it? Against 2.4.23.
> >
> > Just some feedback:
> >
> > echo 511 > /proc/sys/vm/max-readahead
> >
> > brings back the read performance of my 30 disks on 4 controller
> > LVM/RAID0.
>
> Great.
>
Indeed :-) Just to clarify - the modification of max-readahead was
sufficient to "fix" the observed read performance degradation. I did
not apply (or reverse) anything on top of 2.4.22.
Actually 255 would have been sufficient, 511 proved to be a small bit
better :-))
Martin
=====
------------------------------------------------------
Martin Knoblauch
email: k n o b i AT knobisoft DOT de
www: http://www.knobisoft.de
next prev parent reply other threads:[~2003-12-18 14:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-16 12:51 RAID-0 read perf. decrease after 2.4.20 Martin Knoblauch
2003-12-18 13:41 ` Marcelo Tosatti
2003-12-18 14:37 ` Martin Knoblauch [this message]
2004-07-04 23:28 ` Mikael Johansson
2003-12-18 19:13 ` Mike Fedyk
2003-12-18 19:17 ` Marcelo Tosatti
-- strict thread matches above, loose matches on Subject: below --
2003-11-25 9:41 Martin Knoblauch
2003-11-24 10:05 Martin Knoblauch
2003-11-25 5:01 ` Joshua Schmidlkofer
2003-11-20 16:45 Mikael Johansson
2003-11-21 13:47 ` Marcelo Tosatti
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
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