On Sun, Nov 21, 2004 at 10:42:45AM -0500, Alan Cox wrote: > On Sat, Nov 20, 2004 at 11:50:49PM +0100, Ziga Mahkovec wrote: > > 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). > > Disks are very very seek constrained. You get wonderful performance reading > linear data. The moment you read a lot of scattered files or a file with a > lot of segments you will get low performance - even more so on laptops than > desktops yeah we saw that; sorting the list on disk sector shaved 2 seconds off... if we want to save more we'll have to fix the on disk layout to be less spread out. That's not going to be fun...
