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| author | Mike Snitzer <snitzer@redhat.com> | 2015-03-08 00:51:47 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-04-15 12:10:16 -0400 |
| commit | bfebd1cdb497a57757c83f5fbf1a29931591e2a4 (patch) | |
| tree | c4ca9675ad22a45eb6e36b130db0d65d574dd2b3 /drivers/md/dm-mpath.c | |
| parent | 0ce65797a77ee780f62909d3128bf08b9735718b (diff) | |
| download | lwn-bfebd1cdb497a57757c83f5fbf1a29931591e2a4.tar.gz lwn-bfebd1cdb497a57757c83f5fbf1a29931591e2a4.zip | |
dm: add full blk-mq support to request-based DM
Commit e5863d9ad ("dm: allocate requests in target when stacking on
blk-mq devices") served as the first step toward fully utilizing blk-mq
in request-based DM -- it enabled stacking an old-style (request_fn)
request_queue ontop of the underlying blk-mq device(s). That first step
didn't improve performance of DM multipath ontop of fast blk-mq devices
(e.g. NVMe) because the top-level old-style request_queue was severely
limited by the queue_lock.
The second step offered here enables stacking a blk-mq request_queue
ontop of the underlying blk-mq device(s). This unlocks significant
performance gains on fast blk-mq devices, Keith Busch tested on his NVMe
testbed and offered this really positive news:
"Just providing a performance update. All my fio tests are getting
roughly equal performance whether accessed through the raw block
device or the multipath device mapper (~470k IOPS). I could only push
~20% of the raw iops through dm before this conversion, so this latest
tree is looking really solid from a performance standpoint."
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Keith Busch <keith.busch@intel.com>
Diffstat (limited to 'drivers/md/dm-mpath.c')
| -rw-r--r-- | drivers/md/dm-mpath.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index add6391f3f8e..c8f07e5a9a17 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1703,7 +1703,7 @@ out: *---------------------------------------------------------------*/ static struct target_type multipath_target = { .name = "multipath", - .version = {1, 8, 0}, + .version = {1, 9, 0}, .module = THIS_MODULE, .ctr = multipath_ctr, .dtr = multipath_dtr, |