From: Yohan <ytordjman@corp.free.fr>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
Neil Brown <neilb@suse.de>,
"J. Bruce Fields" <bfields@fieldses.org>,
mikevs@xs4all.net
Subject: Re: VM issue causing high CPU loads
Date: Thu, 03 Sep 2009 16:08:55 +0200 [thread overview]
Message-ID: <4A9FCDF7.1090700@corp.free.fr> (raw)
In-Reply-To: <1251986526.18338.29.camel@heimdal.trondhjem.org>
Trond Myklebust wrote:
> On Thu, 2009-09-03 at 15:39 +0200, Yohan wrote:
>
>>> 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.
>>
> OK, so 16 hash buckets are likely to be filled with ~10^6 entries each.
> I can see that might be a performance issue...
>
> So afaics, you did try adjusting the hashtable size. How much larger
> does it have to be before you start to get acceptable performance? If it
> solves your problem we could make hash table sizes adjustable via a
> module parameter, for instance.
>
I run now with a value of 12, and it's great for me...
next prev parent reply other threads:[~2009-09-03 14:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-24 14:23 VM issue causing high CPU loads Yohan
2009-08-24 23:21 ` Andrew Morton
2009-08-26 11:08 ` Mel Gorman
2009-08-26 11:55 ` Yohan
2009-08-26 11:53 ` Yohan
2009-08-27 8:39 ` Yohan
2009-08-31 20:39 ` Yohan
2009-09-03 0:06 ` Andrew Morton
2009-09-03 13:01 ` Trond Myklebust
2009-09-03 13:39 ` Yohan
2009-09-03 14:02 ` Trond Myklebust
2009-09-03 14:08 ` Yohan [this message]
2009-09-03 14:35 ` sunrpc: dynamically allocate credcache hashtables [was: Re: VM issue causing high CPU loads] Miquel van Smoorenburg
2009-09-03 20:05 ` VM issue causing high CPU loads Simon Kirby
2009-09-03 20:49 ` Trond Myklebust
2009-09-03 22:22 ` Simon Kirby
2009-09-04 12:31 ` Trond Myklebust
2009-09-03 21:21 ` Muntz, Daniel
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