Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 3 Aug 2002 20:31:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 3 Aug 2002 20:31:35 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:52754 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Sat, 3 Aug 2002 20:31:34 -0400 Message-ID: <3D4C78F0.5793D6B3@zip.com.au> Date: Sat, 03 Aug 2002 17:44:32 -0700 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-rc5 i686) X-Accept-Language: en MIME-Version: 1.0 To: Daniel Phillips CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Rmap speedup References: <3D4C4DD9.779C057B@zip.com.au> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4593 Lines: 103 Daniel Phillips wrote: > > On Saturday 03 August 2002 23:40, Andrew Morton wrote: > > Running the same test on 2.4: > > > > 2.4.19-pre7: > > ./daniel.sh 35.12s user 65.96s system 363% cpu 27.814 total > > ./daniel.sh 35.95s user 64.77s system 362% cpu 27.763 total > > ./daniel.sh 34.99s user 66.46s system 364% cpu 27.861 total > > > > 2.4.19-pre7+rmap: > > ./daniel.sh 36.20s user 106.80s system 363% cpu 39.316 total > > ./daniel.sh 38.76s user 118.69s system 399% cpu 39.405 total > > ./daniel.sh 35.47s user 106.90s system 364% cpu 39.062 total > > > > 2.4.19-pre7+rmap-13b+your patch: > > ./daniel.sh 33.72s user 97.20s system 364% cpu 35.904 total > > ./daniel.sh 35.18s user 94.48s system 363% cpu 35.690 total > > ./daniel.sh 34.83s user 95.66s system 363% cpu 35.921 total > > > > The system time is pretty gross, isn't it? > > > > And it's disproportional to the increased number of lockings. > > These numbers show a 30% reduction in rmap overhead with my patch, > close to what I originally reported: > > ((35.904 + 35.690 + 35.921) - (27.814 + 27.763 + 27.861)) / > ((39.316 + 39.405 + 39.062) - (27.814 + 27.763 + 27.861)) ~= .70 > > But they also show that rmap overhead is around 29% on your box, > even with my patch: > > (35.904 + 35.690 + 35.921) / (27.814 + 27.763 + 27.861) ~= 1.29 > > Granted, it's still way too high, and we are still in search of the > 'dark cycles'. I'd say that the rmap overhead remains 50%, actually. That's the increase in system time. > Did we do an apples-to-apples comparison of 2.4 to 2.5? Seems 2.4 is a little faster - see the other email. Just another hit on page->flags somewhere would be enough to make that difference. Nothing very obvious stands out in the oprofiles. 2.5.26: c011c7b0 255 0.820833 exit_notify c0131d00 255 0.820833 lru_cache_add c0117d48 257 0.827271 copy_mm c012d078 271 0.872336 filemap_nopage c0113dec 312 1.00431 pgd_alloc c011415c 338 1.08801 do_page_fault c014eb84 379 1.21998 __d_lookup c0134050 385 1.2393 free_page_and_swap_cache c0139a08 405 1.30368 do_page_cache_readahead c0145e08 417 1.3423 link_path_walk c0132f30 428 1.37771 __free_pages_ok c012c3b8 582 1.87343 find_get_page c01db08c 583 1.87665 radix_tree_lookup c0128040 594 1.91206 clear_page_tables c0107b58 650 2.09232 page_fault c0113ea0 682 2.19533 pte_alloc_one c01331c0 785 2.52688 rmqueue c0129868 1146 3.68892 do_anonymous_page c013383c 1485 4.78015 page_cache_release c01284f0 1513 4.87028 zap_pte_range c0129a04 1717 5.52694 do_no_page c01282b0 1726 5.55591 copy_page_range c0129124 6653 21.4157 do_wp_page 2.4.19-pre7: c0140004 144 0.79929 free_page_and_swap_cache c013bbc4 146 0.810391 kmem_cache_alloc c011bf44 148 0.821492 copy_mm c013c290 163 0.904751 kmem_cache_free c01193fc 164 0.910302 do_schedule c011c88c 168 0.932504 do_fork c0155fe4 192 1.06572 link_path_walk c013d6e0 211 1.17118 lru_cache_add c01182d8 220 1.22114 do_page_fault c0122158 226 1.25444 exit_notify c012e5c4 252 1.39876 clear_page_tables c013eee0 292 1.62078 __free_pages_ok c01096cc 404 2.24245 page_fault c013f298 409 2.2702 rmqueue c0161438 440 2.44227 d_lookup c0130c60 443 2.45893 pte_alloc c0134318 634 3.51909 __find_get_page c0130404 660 3.66341 do_anonymous_page c013fa3c 728 4.04085 __free_pages c012e960 972 5.3952 zap_page_range c012e6d8 1031 5.72269 copy_page_range c01306a0 1042 5.78375 do_no_page c012f8a0 3940 21.8694 do_wp_page - 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/