Theodore Tso wrote: > On Thu, May 14, 2009 at 08:21:05PM -0500, Eric Sandeen wrote: >> it should lay out a 4g file in random 1m direct IOs to fragment it and >> get a lot of extents, then launch 2 threads, one each doing random reads >> and random writes of that same file. >> >> I can't make this trip it, though ... > > If all of the blocks are in the page cache, you won't end up calling > ext4_get_blocks(). Try adding a shell script which runs in parallel > doing a "while /bin/true ; do sleep 1; echo 3 > /proc/sys/vm/drop_cache; done". > > - Ted I made sure it was a big enough file, and consumed enough memory on the system before the test, that the entire file couldn't fit in memory. I can try doing the dropping in the bg ... but it should have been going to disk already. -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
