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Message-Id: <200705222037.54741.kernel@kolivas.org>
Date: Tue, 22 May 2007 20:37:54 +1000
From: Con Kolivas <kernel@...ivas.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: Antonino Ingargiola <tritemio@...il.com>,
Nick Piggin <nickpiggin@...oo.com.au>,
Ray Lee <ray-lk@...rabbit.org>, ck list <ck@....kolivas.org>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH] mm: swap prefetch improvements
On Tuesday 22 May 2007 20:25, Ingo Molnar wrote:
> * Con Kolivas <kernel@...ivas.org> wrote:
> > > > there was nothing else running on the system - so i suspect the
> > > > swapin activity flagged 'itself' as some 'other' activity and
> > > > stopped? The swapins happened in 4 bursts, separated by 5 seconds
> > > > total idleness.
> > >
> > > I've noted burst swapins separated by some seconds of pause in my
> > > desktop system too (with sp_tester and an idle gnome).
> >
> > That really is expected, as just about anything, including journal
> > writeout, would be enough to put it back to sleep for 5 more seconds.
>
> note that nothing like that happened on my system - in the
> swap-prefetch-off case there was _zero_ IO activity during the sleep
> period.
Ok, granted it's _very_ conservative. I really don't want to risk its presence
being a burden on anything, and the iowait it induces probably makes it turn
itself off for another PREFETCH_DELAY (5s). I really don't want to cross the
line to where it is detrimental in any way. Not dropping out on a
cond_resched and perhaps making the delay tunable should be enough to make it
a little less "sleepy".
--
-ck
-
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