From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <462C2EDE.4090805@yahoo.com.au> Date: Mon, 23 Apr 2007 13:58:22 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [PATCH] lazy freeing of memory through MADV_FREE References: <46247427.6000902@redhat.com> <20070420135715.f6e8e091.akpm@linux-foundation.org> <462932BE.4020005@redhat.com> <20070420150618.179d31a4.akpm@linux-foundation.org> <4629524C.5040302@redhat.com> <462ACA40.8070407@yahoo.com.au> <462B0156.9020407@redhat.com> <462BFAF3.4040509@yahoo.com.au> <462C2DC7.5070709@redhat.com> In-Reply-To: <462C2DC7.5070709@redhat.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Andrew Morton , linux-kernel , linux-mm , shak , jakub@redhat.com, drepper@redhat.com List-ID: Rik van Riel wrote: > I've added a 5th column, with just your mmap_sem patch and > without my madv_free patch. It is run with the glibc patch, > which should make it fall back to MADV_DONTNEED after the > first MADV_FREE call fails. Thanks! (I edited slightly so it doesn't wrap) > vanilla new glibc madv_free mmap_sem both > threads > > 1 610 609 596 534 545 > 2 1032 1136 1196 1180 1200 > 4 1070 1128 2014 2027 2024 > 8 1000 1088 1665 2089 2087 > 16 779 1073 1310 2012 1999 > > > Not doing the mprotect calls is the big one I guess, especially > the fact that we don't need to take the mmap_sem for writing. Yes. > With both our patches, single and two thread performance with > MySQL sysbench is somewhat better than with just your patch, > 4 and 8 thread performance are basically the same and just > your patch gives a slight benefit with 16 threads. > > I guess I should benchmark up to 64 or 128 threads tomorrow, > to see if this is just luck or if the cache benefit of doing > the page faults and reusing hot pages is faster than not > having page faults at all. > > I should run some benchmarks on other systems, too. Some of > these results could be an artifact of my quad core CPU. The > results could be very different on other systems... I'm getting the 16 core box out of retirement as we speak :) -- SUSE Labs, Novell Inc. -- 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