On Thu, Apr 07 2016 at 10:58am -0400, Hannes Reinecke <hare@xxxxxxx> wrote: > On 03/31/2016 10:04 PM, Mike Snitzer wrote: > > I developed these changes some weeks ago but have since focused on > > regression and performance testing on larger NUMA systems. > > > > For regression testing I've been using mptest: > > https://github.com/snitm/mptest > > > > For performance testing I've been using a null_blk device (with > > various configuration permutations, e.g. pinning memory to a > > particular NUMA node, and varied number of submit_queues). > > > > By eliminating multipath's heavy use of the m->lock spinlock in the > > fast IO paths serious performance improvements are realized. > > > [ .. ] > > Jeff Moyer has been helping review these changes (and has graciously > > labored over _really_ understanding all the concurrency at play in DM > > mpath) -- his review isn't yet complete but I wanted to get this > > patchset out now to raise awareness about how I think DM multipath > > will be changing (for inclussion during the Linux 4.7 merge window). > > > > Mike Snitzer (4): > > dm mpath: switch to using bitops for state flags > > dm mpath: use atomic_t for counting members of 'struct multipath' > > dm mpath: move trigger_event member to the end of 'struct multipath' > > dm mpath: eliminate use of spinlock in IO fast-paths > > > > drivers/md/dm-mpath.c | 351 ++++++++++++++++++++++++++++---------------------- > > 1 file changed, 195 insertions(+), 156 deletions(-) > > > Finally got around to test this. > The performance is comparable to the previous (RCU-ified) patchset, > however, this one is the far superious approach. > In fact, the first two are pretty much identical to what I've > already had, but I've shirked at modifying the path selectors. > So well done here. Awesome, thanks for reviewing and testing, very much appreciated. I'll get this set staged in linux-next for 4.7 shortly. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
