dm-multipath low performance with blk-mq

[Hannes Reinecke]

On 02/04/2016 02:54 PM, Mike Snitzer wrote:
> On Thu, Feb 04 2016 at  1:54am -0500,
> Hannes Reinecke <hare at suse.de> wrote:
> 
[ .. ]
>> But anyway, I'll be looking at your patches.
> 
> Thanks, sadly none of the patches are going to fix the performance
> problems but I do think they are a step forward.
> 
Hmm. I've got a slew of patches converting dm-mpath to use atomic_t
and bitops; with that we should be able to move to rcu for path
lookup and do away with most of the locking.
Quite raw, though; drop me a mail if you're interested.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare at suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)