Messages in this thread | | | Date | Thu, 03 Sep 2009 15:39:37 +0200 | From | Yohan <> | Subject | Re: VM issue causing high CPU loads |
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>>> 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. >> > OK. Could we please have some more details about the actual workload involved here? > I add a new server CPU graph and 60s readprofile on the bugzilla
> As far as I can see, there is no RPCSEC_GSS involved, so credentials > should never expire. They will be reused as long as processes aren't > switching between thousands and thousands of different combinations of > uid, gid and groups. My servers are imap servers. Foreach user (~15 million) it have a specific uid over ~10 nfs netapp storage.
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