On Mon, 31 Aug 2009 22:39:20 +0200 Yohan <ytordjman@xxxxxxxxxxxx> wrote: > Yohan wrote: > > Andrew Morton wrote: > >> On Mon, 24 Aug 2009 16:23:22 +0200 > >> Yohan <kernel@xxxxxxxxxxxxxxxxxxxxxx> wrote: > >>> Hi, > >>> > >>> Is someone have an idea for that : > >>> > >>> http://bugzilla.kernel.org/show_bug.cgi?id=14024 > >>> > >> Please generate a kernel profile to work out where all the CPU tie is > >> being spent. Documentation/basic_profiling.txt is a starting point. > >> > > I post some new reports, it seems that the problem is in > > rpcauth_lookup_credcache ... Thanks, that helps a lot. > > for information, this is an imap mail server that mounts ~10 netapp > > over ~300 mountpoints.. > I saw that : http://patchwork.kernel.org/patch/24747/ I wonder what happened with Miquel's patch? > I did only: > > --- linux-2.6.27.21/include/linux/sunrpc/auth.h 2009-03-23 23:04:09.000000000 +0100 > +++ linux-2.6.27.21/include/linux/sunrpc/auth.h 2009-05-19 16:02:35.000000000 +0200 > @@ -62,8 +62,12 @@ > */ > - #define RPC_CREDCACHE_HASHBITS 4 > + #define RPC_CREDCACHE_HASHBITS 12 > > > And i test it in prod since sunday: i only have 36% of one core used by > system > versus more than 3 cores used by system in another server that did a > drop_caches at morning... > OK, but it's still pretty bad. Let's tell the NFS guys. In http://bugzilla.kernel.org/show_bug.cgi?id=14024 we appear to have a major meltdown caused by the linear search in rpcauth_lookup_credcache() with Yohan's workload. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
