Bug#692957: linux-image-3.2.0-4-amd64: NFS server causes high load on 3.2 kernel

[Ben Hutchings <ben@decadent.org.uk>]

-------- Forwarded Message --------
From: Karsten Suehring <suehringbugs@gmail.com>
To: Ben Hutchings <ben@decadent.org.uk>
Subject: Re: Bug#692957: linux-image-3.2.0-4-amd64: NFS server causes high load on 3.2 kernel
Date: Sun, 11 Nov 2012 22:58:11 +0100


        I don't think load figures from a VM are likely to be
        meaningful.

I agree for detailed measurements, I guess in order of magnitude it's
fine to draw some conclusions. Also it's the only way for me to run lots
of different test setups (especially being at home). I can do some more
measurements on a real system tomorrow.

 

        That fix was backported into 3.2.29, so we have it already.  Are
        you
        definitely running the above version (3.2.32-1) on the server?

I was running the bug report tool on the actual server VM and just
checked the version and performance numbers again.

root@debian-server:~# uname -a
Linux debian-server 3.2.0-4-amd64 #1 SMP Debian 3.2.32-1 x86_64
GNU/Linux

But it seems the patch had some positive effect, which I didn't notice
before. On the Ubuntu Server I see a constant load of 40%. On Debian I
have more an average around 25-30% with peaks going up to 40%, but also
peaks in the other direction going down below 10%.

But as I said before, it's not the same as if I boot the old 2.6 kernel
on the same machine:

root@debian-server:~# uname -a
Linux debian-server 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012
x86_64 GNU/Linux

With that kernel (an nothing else changed) the numbers go down to around
10%.

Thanks for looking into this,
Karsten