From: Andrew Morton <akpm@zip.com.au>
To: Simon Kirby <sim@netnation.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: fsync delays for a long time.
Date: Fri, 15 Feb 2002 11:07:26 -0800 [thread overview]
Message-ID: <3C6D5C6E.78047200@zip.com.au> (raw)
In-Reply-To: <Pine.SGI.4.31.0202140951330.3076325-100000@fsgi03.fnal.gov> <E16bPqi-0000c5-00@the-village.bc.nu> <3C6C2342.5044B738@zip.com.au>, <3C6C2342.5044B738@zip.com.au> <20020215172436.GA6842@netnation.com>
Simon Kirby wrote:
>
> Not sure if this is related, but I still can't get 2.4 or 2.5 kernels to
> actually read and write at the same time during a large file copy between
> two totally separate devices (eg: from hda1 to hdc1). "vmstat 1" shows
> reads with no writing for about 6-8 seconds followed by writes with no
> reading for about 5-6 seconds, repeat.
That's different.
It tends to be the case that when the dirty-data-generator hits
a particular threshold, it blocks while we write out vast amounts
of data. So the throughput is very lumpy.
It's probable that it can be tamed a bit by fiddling with the
/proc/sys/vm/bdflush parameters.
> Is there a patch available that could fix this?
The -aa patches fiddle extensively with the bdflush thresholds and logic.
There's stuff in there which might addresses this.
-
next prev parent reply other threads:[~2002-02-15 19:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-14 16:03 fsync delays for a long time Alexander Moibenko
2002-02-14 17:39 ` Alan Cox
2002-02-14 20:51 ` Andrew Morton
2002-02-14 21:09 ` Alan Cox
2002-02-14 21:12 ` Alexander Moibenko
2002-02-14 21:37 ` Alan Cox
2002-02-14 21:26 ` Alexander Moibenko
2002-02-14 21:41 ` Andrew Morton
2002-02-14 22:18 ` Alexander Moibenko
2002-02-14 21:20 ` Andrew Morton
2002-02-14 21:38 ` Alan Cox
2002-02-15 16:48 ` Stephen C. Tweedie
2002-02-15 17:24 ` Simon Kirby
2002-02-15 19:07 ` Andrew Morton [this message]
2002-02-15 19:21 ` Simon Kirby
2002-02-17 12:47 ` Bill Davidsen
2002-02-17 16:45 ` Simon Kirby
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