From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3D3F893D.4074CDE5@zip.com.au> Date: Wed, 24 Jul 2002 22:14:37 -0700 From: Andrew Morton MIME-Version: 1.0 Subject: Re: page_add/remove_rmap costs References: <3D3E4A30.8A108B45@zip.com.au> <20020725045040.GD2907@holomorphy.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: William Lee Irwin III Cc: "linux-mm@kvack.org" List-ID: William Lee Irwin III wrote: > > On Tue, Jul 23, 2002 at 11:33:20PM -0700, Andrew Morton wrote: > > Been taking a look at the page_add_rmap/page_remove_rmap cost in 2.5.27 > > on the quad pIII. The workload is ten instances of this script running > > concurrently: > > The workload is 16 instances of the same script running on a 16 cpu NUMA-Q > with 16GB of RAM. oprofile results attached. These results look funny. What I do is: 1) rm -rf /var/opd 2) start test 3) op_start --map-file=/boot/System.map --vmlinux=/boot/vmlinux --ctr0-event=CPU_CLK_UNHALTED --ctr0-count=600000 4) sleep 20 5) op_stop 6) oprofpp -l -i /boot/vmlinux > > c0105340 3309367 51.0125 default_idle /boot/vmlinux-2.5.28-3 How come? > c0135667 1095488 16.8865 .text.lock.page_alloc /boot/vmlinux-2.5.28-3 zone->lock? > 00000fec 475107 7.32358 dump_one /lib/modules/2.5.28-3/kern that's part of oprofile. > el/arch/i386/oprofile/oprofile.o > c0129c10 349662 5.3899 do_anonymous_page /boot/vmlinux-2.5.28-3 OK. > c01353e4 236718 3.64891 get_page_state /boot/vmlinux-2.5.28-3 whoa. Who's calling that so often? Any patches applied there? > c0112a84 213189 3.28622 load_balance /boot/vmlinux-2.5.28-3 I thought you'd disabled this? > c013d31c 71599 1.10367 page_add_rmap /boot/vmlinux-2.5.28-3 > c013d3cc 67122 1.03466 page_remove_rmap /boot/vmlinux-2.5.28-3 page_add_rmap is more expensive than page_remove_rmap. So again, the list length isn't the #1 problem. > c013d85a 64302 0.991189 .text.lock.rmap /boot/vmlinux-2.5.28-3 pte_chain_freelist_lock? -- 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/