Re: VM issue causing high CPU loads

From: Yohan
Date: Thu Sep 03 2009 - 10:09:05 EST

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...

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