On 6/26/12 3:30 PM, Ric Wheeler wrote: > Thanks! Eric is also running some tests to evaluate the impact of various techniques :) > > ric Yup forgive me for interjecting actual numbers into the discussion ;) I tried running this fio recipe on v3.3, which I think does a decent job of emulating the situation (fallocate 1G, do random 1M writes into it, with fsyncs after each): [test] filename=testfile rw=randwrite size=1g filesize=1g bs=1024k ioengine=sync fallocate=1 fsync=1 Stock ext4 (3 tests w/ file remove & cache drop in between): WRITE: io=1024.0MB, aggrb=16322KB/s, minb=16713KB/s, maxb=16713KB/s, mint=64243msec, maxt=64243msec WRITE: io=1024.0MB, aggrb=16249KB/s, minb=16639KB/s, maxb=16639KB/s, mint=64528msec, maxt=64528msec WRITE: io=1024.0MB, aggrb=16370KB/s, minb=16763KB/s, maxb=16763KB/s, mint=64052msec, maxt=64052msec With the patch which exposes other users' data: WRITE: io=1024.0MB, aggrb=17840KB/s, minb=18268KB/s, maxb=18268KB/s, mint=58776msec, maxt=58776msec WRITE: io=1024.0MB, aggrb=17841KB/s, minb=18269KB/s, maxb=18269KB/s, mint=58773msec, maxt=58773msec WRITE: io=1024.0MB, aggrb=17828KB/s, minb=18255KB/s, maxb=18255KB/s, mint=58816msec, maxt=58816msec so about 10% faster than without. XFS, FWIW: WRITE: io=1024.0MB, aggrb=24008KB/s, minb=24584KB/s, maxb=24584KB/s, mint=43675msec, maxt=43675msec WRITE: io=1024.0MB, aggrb=24069KB/s, minb=24647KB/s, maxb=24647KB/s, mint=43564msec, maxt=43564msec WRITE: io=1024.0MB, aggrb=24054KB/s, minb=24632KB/s, maxb=24632KB/s, mint=43591msec, maxt=43591msec which is 35% faster than ext4 with the risky patch. Haven't yet tried overwrites or done any tracing or profiling, but I think the fio recipe is a decent demonstrator, I'll try the overwrites etc in a bit when I get a moment. -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
