On Fri, Feb 12 2016 at 10:18am -0500, Hannes Reinecke <hare@xxxxxxx> wrote: > On 02/11/2016 04:34 PM, Mike Snitzer wrote: > > On Wed, Feb 10 2016 at 8:50pm -0500, > > Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > >> On Tue, Feb 09 2016 at 7:45pm -0500, > >> Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > >> > >>> > >>> OK, I took a crack at embracing RCU. Only slightly better performance > >>> on my single NUMA node testbed. (But I'll have to track down a system > >>> with multiple NUMA nodes to do any justice to the next wave of this > >>> optimization effort) > >>> > >>> This RCU work is very heavy-handed and way too fiddley (there could > >>> easily be bugs). Anyway, please see: > >>> http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/commit/?h=devel2&id=d80a7e4f8b5be9c81e4d452137623b003fa64745 > >>> > >>> But this might give you something to build on to arrive at something > >>> more scalable? > >> > >> I've a bit more polished version of this work (broken up into multiple > >> commits, with some fixes, etc) here: > >> http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/log/?h=devel3 > >> > >> Hannes and/or Sagi, if you get a chance to try this on your NUMA system > >> please let me know how it goes. > > > > Initial review has uncovered some locking problems with the current code > > (nothing that caused crashes or hangs in my testing but...) so please > > hold off on testing until you hear from me (hopefully tomorrow). > > > Good news is that I've managed to hit the roof for my array with the > devel2 version of those patches. (And a _heavily_ patched-up lpfc > driver :-) > So from that perspective everything's fine now; we've reached the > hardware limit for my setup. > Which in itself is quite impressive; beating Intel P3700 with 16FC > is not bad methinks :-) > > So thanks for all your work here. Ah, that's really good news! But devel2 is definitely _not_ destined for upstream. 'devel3' is much closer to "ready". But your testing and review would really push it forward. Please see/test: http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/log/?h=devel3 Also, please read this header: http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/commit/?h=devel3&id=65a01b76502dd68e8ca298ee6614c0151b677f4a Even with devel2 I hacked it such that repeat_count > 1 is effectively broken. I'm now _seriously_ considering deprecating repeat_count completely (adding a DMWARN that will inform the user. e.g.: "repeat_count > 1 is no longer supported"). I see no point going to great lengths to maintain a dm-mpath feature that was only a hack for when dm-mpath was bio-based. What do you think? Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
