On Sat, Apr 13 2013 at 3:33pm -0400, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Sat, Apr 13 2013 at 12:09pm -0400, > Joe Thornber <thornber@xxxxxxxxxx> wrote: > > > Hi Darrick, > > > > On Thu, Apr 11, 2013 at 12:22:39AM -0700, Darrick J. Wong wrote: > > > Hi all, > > > > > > Lately I've been having some fun playing with bcache, dmcache, and enhanceio. > > > > I pushed some tweaks to the mq policy today to my thin-dev tree. They > > show some improvements to these fio based tests. > > > > In addition I've written a blog post trying to explain what's going on in dm-cache: > > http://device-mapper.org/blog/2013/04/13/benchmarking-dm-cache-with-fio/ > > Darrick, > > Joe has a few other dm-cache-target.c changes in his thin-dev branch > that are required in order to realize the gains from his mq changes. I > haven't yet isolated which changes are important but if I just use the > 3.9-rc6's dm-cache-tagret.c with thin-dev's mq changes I cannot > reproduce the improved performance Joe mentions in his blog post. I've now isolated the dm-cache-target.c commit in Joe's thin-dev that is important to have in conjunction with the mq changes (from commit 7362f43a): commit f134e6382a534dd3622c3850e4824ae5929885d9 Author: Joe Thornber <ejt@xxxxxxxxxx> Date: Wed Mar 27 14:46:57 2013 +0000 [dm-cache] Change the default migration_threshold to something more suitable. diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 8a4bcf3..f215307 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -1948,7 +1948,7 @@ static sector_t calculate_discard_block_size(sector_t cache_block_size, return discard_block_size; } -#define DEFAULT_MIGRATION_THRESHOLD (2048 * 100) +#define DEFAULT_MIGRATION_THRESHOLD 2048 static int cache_create(struct cache_args *ca, struct cache **result) { -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
