On Sat, 2004-11-20 at 18:47 +0100, Arjan van de Ven wrote: > > Yeah I guess the fact that disk caches are loaded on a per-file basis > > doesn't help either. Because in theory: stat-ing your list takes about > > 3 sec and readahead on a tarball is instantaneous (both of course > > without boot-time readahead). > > ok here is another try; I hacked up a tool to sort the list in disk > order. Arjan, not quite the improvement I expected, but it does shave off an additional 2 seconds: http://www.klika.si/ziga/bootchart/bootchart-sortreadahead.png This chart includes data from iostat (sysstat package). Notice how the disk is fully utilized (%util) during readahead, but the throughput (rkB/s) is *really* low. This could very well be a problem with my hard disk. hdparm seems fine though (and I checked the parameters before running readahead). Let me know if you'd find any other iostat columns useful in the chart. The log file is here: http://www.klika.si/ziga/bootchart/boot.io.log.sortreadahead.gz Anyway, the bootchart scripts and source code will be on SourceForge tomorrow so people will be able to post their results. Thanks, -- Ziga
