From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Mario Vanoni <vanonim@dial.eunet.ch>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: NFS problem after 2.4.19-pre3, not solved
Date: 14 May 2002 10:06:17 +0200 [thread overview]
Message-ID: <shswuu7f91i.fsf@charged.uio.no> (raw)
In-Reply-To: <3CDC4962.4B9393D7@dial.eunet.ch> <15582.65383.578660.222454@charged.uio.no> <20020513184050.D22902@dualathlon.random>
>>>>> " " == Andrea Arcangeli <andrea@suse.de> writes:
> the thing that makes the difference is the backout-cto patch
> according those numbers and I doubt it is influencing the page
> replacement in any way (is kernel-side memory pressure going to
> increase significantly with cto?).
No. The only possibility I can see is if the extra checks are causing
extra cache invalidations. I don't why that should be the case, but
then again I'm not able to reproduce those numbers...
> 2.4.19-pre3 vanilla first time after boot 5m15s, then 1m56s
> 1m57s 1m56s 1m56s 1m57s
> 2.4.19-pre4 vanilla 5m20s, then 4m00s 4m01s 4m00s 4m01s 4m01a
> 2.4.19-pre4-nfs-backout-cto, from pr8aa2, 2 Hunks 5m13a, then
> 1m57s 1m58s 1m57s 1m58s 1m59s
> nfs-backout-cto is appended. Now if the previous kernel was
> buggy and it was not invalidating "invalid" cache then cto is
> right, otherwise it sounds like the cto patch is invalidating
> more cache than necessary.
Check the patch: it doesn't invalidate the cache when the mtime stays
the same. A tcpdump would show whether this is the case or not.
I would be interested to see if this is something that is related to
nfs-server only. (I.e. whether or not Mario can see the same problem
with knfsd.)
Cheers,
Trond
prev parent reply other threads:[~2002-05-14 8:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-10 22:27 NFS problem after 2.4.19-pre3, not solved Mario Vanoni
2002-05-10 21:17 ` Andrea Arcangeli
2002-05-11 21:37 ` Mario Vanoni
2002-05-12 23:48 ` Trond Myklebust
2002-05-13 16:40 ` Andrea Arcangeli
2002-05-14 8:06 ` Trond Myklebust [this message]
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