From mboxrd@z Thu Jan 1 00:00:00 1970 From: Con Kolivas Subject: Re: [PATCH] mm: swap prefetch improvements Date: Tue, 22 May 2007 20:20:57 +1000 References: <20070430162007.ad46e153.akpm@linux-foundation.org> <20070521160029.GA28715@elte.hu> <5486cca80705220315oe4a42a2x366cff682333075c@mail.gmail.com> In-Reply-To: <5486cca80705220315oe4a42a2x366cff682333075c@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705222020.58474.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Antonino Ingargiola Cc: Ingo Molnar , Nick Piggin , Ray Lee , ck list , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Tuesday 22 May 2007 20:15, Antonino Ingargiola wrote: > 2007/5/21, Ingo Molnar : > > * Con Kolivas wrote: > > > > A suggestion for improvement: right now swap-prefetch does a small > > > > bit of swapin every 5 seconds and stays idle inbetween. Could this > > > > perhaps be made more agressive (optionally perhaps), if the system > > > > is not swapping otherwise? If block-IO level instrumentation is > > > > needed to determine idleness of block IO then that is justified too > > > > i think. > > > > > > Hmm.. The timer waits 5 seconds before trying to prefetch, but then > > > only stops if it detects any activity elsewhere. It doesn't actually > > > try to go idle in between but it doesn't take much activity to put it > > > back to sleep, hence detecting yet another "not quite idle" period and > > > then it goes to sleep again. I guess the sleep interval can actually > > > be changed as another tunable from 5 seconds to whatever the user > > > wanted. > > > > 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. -- -ck -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org