site_archiver@lists.apple.com Delivered-To: darwin-dev@lists.apple.com On Aug 28, 2009, at 12:33 AM, Jonas Maebe wrote: Do these results mean that I should be digging somewhere else? Here are the gory details... cold startup for Safari cold startup for Firefox Startup as measured by DTrace --- ./cold.sh startup.d Total: 10001.723521ms --- It only takes 0.3s to run the initializers according to dyld above. Where did the other 9.7s go? cold.sh is rather simple --- #!/bin/bash and the startup.d script doesn't do much either --- #pragma D option quiet BEGIN { start = timestamp; } /* stop tracing here */ mozilla$target:::main-entry { exit(0); } Just in case, here are the warm startup stats for Firefox --- fastest mac firefox! http://wagerlabs.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.appl... The statistics that you posted previously show that dyld is only taking about 50ms during Firefox' startup. Even if you could reduce that by 90%, it wouldn't really make a lot of difference given the total startup time. So I'm not sure where the low-hanging fruit is here... By low-hanging fruit I meant a measurement approach, not being able to improve results. I thought it would be rather quick to test the shared cache theory and prove it right or wrong. It appears, though, that 1) under no circumstances does update_dyld_shared_cache wants to put XUL in the cache, even if I try to force it, and 2) it doesn't matter. Proving this was quick, thus low-hanging fruit. There's a large difference between cold startup dyld statistics (25-50ms) and warm startup ones (700ms+). There's also a baffling lack of difference between Firefox and Safari cold stats, despite Safari pulling everything from the cache and Firefox using a large number of non-cached dylibs. If so then I cannot explain the difference between startup time as reported by my DTrace script and the dyld statistics. Note that I'm using the Apple 256Gb SSD in my 2.93Ghz unibody MacBook Pro. I thought initially that startup time reported by DTrace should equal the statistics reported by dyld but it's a difference of less than 1s for dyld and almost 10s for dtrace. --- sync && purge && DYLD_PRINT_STATISTICS=1 /Applications/Safari.app/ Contents/MacOS/Safari total time: 696.9 milliseconds (100.0%) total images loaded: 116 (114 from dyld shared cache, 114 needed no fixups) total segments mapped: 5, into 30 pages with 10 pages pre-fetched total images loading time: 204.9 milliseconds (29.4%) total rebase fixups: 1,298 total rebase fixups time: 0.1 milliseconds (0.0%) total binding fixups: 2,476 total binding symbol lookups: 234, average images searched per symbol: 1.6 total binding fixups time: 80.5 milliseconds (11.5%) total bindings lazily fixed up: 3 of 901 total init time time: 411.3 milliseconds (59.0%) total images with weak exports: 1 --- --- total time: 731.2 milliseconds (100.0%) total images loaded: 106 (93 from dyld shared cache, 56 needed no fixups) total segments mapped: 49, into 5903 pages with 684 pages pre-fetched total images loading time: 235.3 milliseconds (32.1%) total rebase fixups: 149,011 total rebase fixups time: 3.7 milliseconds (0.5%) total binding fixups: 24,932 total binding symbol lookups: 797, average images searched per symbol: 2.3 total binding fixups time: 149.9 milliseconds (20.5%) total bindings lazily fixed up: 45 of 19,109 total init time time: 342.2 milliseconds (46.8%) total images with weak exports: 3 --- My DTrace script measures time to reach a static probe that fires as soon as main is entered. I thought that the only thing that happens before main is the fixup of shared libraries and the running of static initializers. cmd="./Minefield.app/Contents/MacOS/firefox-bin -no-remote -foreground -P 2" sync && purge && dtrace -x dynvarsize=64m -x evaltime=exec -c "$cmd" - wZs $1 --- END { this->total = timestamp - start; printf("Total: %u.%06ums\n", this->total / 1000000, this->total % 1000000); } --- total time: 25.9 milliseconds (100.0%) total images loaded: 106 (93 from dyld shared cache, 56 needed no fixups) total segments mapped: 49, into 5903 pages with 684 pages pre-fetched total images loading time: 5.6 milliseconds (21.7%) total rebase fixups: 149,011 total rebase fixups time: 3.0 milliseconds (11.6%) total binding fixups: 24,932 total binding symbol lookups: 797, average images searched per symbol: 2.3 total binding fixups time: 3.0 milliseconds (11.6%) total bindings lazily fixed up: 45 of 19,109 total init time time: 14.3 milliseconds (55.0%) total images with weak exports: 3 This email sent to site_archiver@lists.apple.com