On Tue, 2010-09-14 at 20:56 +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > Having multiple CPUs trying to do the same cache shrinking work can > be actively harmful to perforamnce when the shrinkers land in the > same AGs. They then lockstep on perag locks, causing contention and > slowing each other down. Reclaim walking is sufficiently efficient > that we do no need parallelism to make significant progress, so stop > parallel access at the door. > > Instead, keep track of the number of objects the shrinkers want > cleaned and make sure the single running shrinker does not stop > until it has hit the threshold that the other shrinker calls have > built up. > > This increases the cold-cache unlink rate of a 8-way parallel unlink > workload from about 15,000 unlinks/s to 60-70,000 unlinks/s for the > same CPU usage (~700%), resulting in the runtime for a 200M inode > unlink workload dropping from 4h50m to just under 1 hour. This is an aside, but... Shrinking still hits the first AG's more than the rest, right? I.e. if AG 0 has nr_to_scan reclaimable inodes, no other AG's get their inodes reclaimed? Anyway, this change looks good. Reviewed-by: Alex Elder <aelder@xxxxxxx> > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > Reviewed-by: Christoph Hellwig <hch@xxxxxx> > --- > fs/xfs/linux-2.6/xfs_sync.c | 21 +++++++++++++++++++-- > fs/xfs/xfs_mount.h | 2 ++ > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c > index d59c4a6..bc54cd6 100644 . . . _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
