On Fri 05-06-09 20:18:15, Chris Mason wrote: > On Fri, Jun 05, 2009 at 11:14:38PM +0200, Jan Kara wrote: > > On Fri 05-06-09 21:15:28, Jens Axboe wrote: > > > On Fri, Jun 05 2009, Frederic Weisbecker wrote: > > > > The result with noop is even more impressive. > > > > > > > > See: http://kernel.org/pub/linux/kernel/people/frederic/dbench-noop.pdf > > > > > > > > Also a comparison, noop with pdflush against noop with bdi writeback: > > > > > > > > http://kernel.org/pub/linux/kernel/people/frederic/dbench-noop-cmp.pdf > > > > > > OK, so things aren't exactly peachy here to begin with. It may not > > > actually BE an issue, or at least now a new one, but that doesn't mean > > > that we should not attempt to quantify the impact. > > What looks interesting is also the overall throughput. With pdflush we > > get to 2.5 MB/s + 26 MB/s while with per-bdi we get to 2.7 MB/s + 13 MB/s. > > So per-bdi seems to be *more* fair but throughput suffers a lot (which > > might be inevitable due to incurred seeks). > > Frederic, how much does dbench achieve for you just on one partition > > (test both consecutively if possible) with as many threads as have those > > two dbench instances together? Thanks. > > Is the graph showing us dbench tput or disk tput? I'm assuming it is > disk tput, so bdi may just be writing less? Good, question. I was assuming dbench throughput :). Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
