On Thu 13-10-11 22:39:39, Wu Fengguang wrote: > > > + long pause = 1; > > > + long max_pause = dirty_writeback_interval ? > > > + msecs_to_jiffies(dirty_writeback_interval * 10) : > > > + HZ; > > > > It's better not to put the flusher to sleeps more than 10ms, so that > > when the condition changes, we don't risk making the storage idle for > > too long time. > > Yeah, the one big regression case > > 3.1.0-rc8-ioless6a+ 3.1.0-rc8-ioless6-requeue6+ > ------------------------ ------------------------ > 47.07 -15.5% 39.78 thresh=1M/xfs-2dd-4k-8p-4096M-1M:10-X > > is exactly caused by the large sleep: the attached graphs are showing > one period of no-progress on the number of written pages. Thanks for the tests! Interesting. Do you have trace file from that run? I see the writeback stalled for 20s or so which is more than dirty_writeback_centisecs so I think something more complicated must have happened. 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
