On Thu, 2014-07-10 at 09:41 +1000, NeilBrown wrote: > autofs4 currently doesn't support RCU-walk - it immediately > aborts any attempt at RCU-walk to force REF-walk for path name > lookup. > > This can cause a significant performance impact on multi-core > systems. > I have a client with a test case which spends >80% of its time > waiting for spinlocks with a "make -j 40" on a 40 core system. Right, sounds worth the effort. > > This patchset aims to remove most of these spinlocks. To be fully > effective in the particular case it needs a second patch set which > makes NFS RCU-walk friendly, but one thing at a time. > > This has only been lightly tested so far so I'm really after feed-back > rather than to have the patch set accepted, though the first two > patches are trivial and could be taken immediately. I've only scanned the patches so far, I'll need to spend a bit more time on them before I can comment. I'm going to be pressed for time for at least several days so I won't be able to get to this right away. I expect the submount_test I use to stress path walking and expire to mount transitions will likely be a good test to use. I haven't used it in my personal environment for quite a while now so I'll need to have a look around and see if I can still find a suitable set of scripts. Otherwise I'll need to decouple it from the RedHat automated test environment. > > The last two patches are the most interesting so review comments on > those are particularly welcome. Again I haven't looked closely at these but don't you mean the last three patches or am I just fussing over an obviously straight forward patch 3? Thanks for your effort Bruce, Ian -- To unsubscribe from this list: send the line "unsubscribe autofs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
