Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 19 Mar 2002 03:59:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 19 Mar 2002 03:59:01 -0500 Received: from garrincha.netbank.com.br ([200.203.199.88]:40711 "HELO netbank.com.br") by vger.kernel.org with SMTP id ; Tue, 19 Mar 2002 03:58:50 -0500 Date: Tue, 19 Mar 2002 05:58:29 -0300 (BRT) From: Rik van Riel X-X-Sender: riel@imladris.surriel.com To: "Martin J. Bligh" Cc: Andrea Arcangeli , linux-kernel Subject: Re: Scalability problem (kmap_lock) with -aa kernels In-Reply-To: <47390000.1016511942@flay> Message-ID: X-spambait: aardvark@kernelnewbies.org X-spammeplease: aardvark@nl.linux.org MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 18 Mar 2002, Martin J. Bligh wrote: > OK, I finally got the -aa kernel series running in conjunction with the > NUMA-Q discontigmem stuff. For some reason which I haven't debugged > yet 2.4.19-pre3-aa2 won't boot on the NUMA-Q even without the discontigmem > stuff in ... so I went back to 2.4.19-pre1-aa1, which I knew worked from > last time around (thanks again for that patch). > > So just comparing aa+discontigmem to standard 2.4.18+discontigmem, I see > kernel compile times are about 35s vs 26.5s .... That's probably Andrea's pte-highmem code, which uses the global kmap pool instead of doing cpu-local atomic kmaps. He's been told about this becoming a scalability problem but didn't believe it since I didn't have any numbers for him. Maybe he believes it now since you've measured it ;) > standard: > > 23991 total 0.0257 > 7679 default_idle 147.6731 > 3044 _text_lock_dcache 8.7221 > 2340 _text_lock_swap 43.3333 > 1160 do_anonymous_page 3.4940 > ... > 109 kmap_high 0.3028 > 46 _text_lock_highmem 0.4071 > > andrea: > 38549 total 0.0405 > 13102 _text_lock_highmem 108.2810 > 8627 default_idle 165.9038 > 2578 kunmap_high 14.3222 > 2556 kmap_high 6.0857 > 1242 do_anonymous_page 3.2684 > 1052 _text_lock_swap 22.8696 > Andrea - is this your new highmem pte stuff doing this? > Or is that not even in your tree as yet? Would be a shame if that's > the problem as I really want to get the highmem pte stuff - allows > me to put processes pagetables on their own nodes .... You really want the pte-highmem by Arjan and Ingo, which uses kmap_atomic (which is CPU-local and doesn't suffer the same scalability problem as the global kmap pool). regards, Rik -- http://www.surriel.com/ http://distro.conectiva.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/