On Thu, Aug 04, 2011 at 10:04:29AM -0400, Chris Mason wrote: > Excerpts from Simon Kirby's message of 2011-08-03 21:32:10 -0400: > > Perhaps as a further clue as to what is going on, on this same backup box > > after all of the rsyncs are finished/killed and a good amount of time has > > passed (no cleaner processes running in the background or anything), > > "sync" is still consistently takes ~4 minutes to run, and pushes out a > > lot to disk every time it is run. Example: > > > > echo 3 > /proc/sys/vm/drop_caches > > sync > > echo 3 > /proc/sys/vm/drop_caches > > sync > > vmstat 1 & > > time sync > > Just to confirm, the profiling during this time shows your system time > is all in rb_next?
Correct, rb_next() called from setup_cluster_no_bitmap(). Also, much of the other CPU time is spent spinning (on refill_lock, I think). It's in this state again now (just one overnight backup run does it). It doesn't seem to happen for the first few hours, but shows up by the next morning. Simon- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
