Re: 2.6.9: performance issues on Via Epia

From: Denis Vlasenko
Date: Tue Oct 19 2004 - 16:02:53 EST


On Tuesday 19 October 2004 18:04, Alistair John Strachan wrote:
> Hi,
>
> I recently upgraded from 2.6.8.1 to 2.6.9 (the release, not -final) on my Via
> Epia 5000 router. Now when I transfer files from the machine's HD vsftpd can
> only achieve 3MB/s.

> I believe this is some performance problem specifically related to XFS, or
> something specific to the local VM, because if I transfer from an NFS mounted
> directory on the same machine, vsftpd easily achieves the 10MB/s I'm used to.

Sound like 'DMA off' problem.

> Top shows something typical to this during transfers from the machine's local
> HD;
>
> Cpu(s): 0.7% us, 9.2% sy, 0.0% ni, 0.3% id, 84.5% wa, 5.3% hi, 0.0% si
>
> Which seems like an awful lot of wait time. Anybody got any suggestions of
> where to start reverting patches? The amount of difference between 2.6.8.1
> and 2.6.9 is quite daunting.

Binary search is converging quickly.

> By the way, copying a file locally on the system from the same partition to
> another directory is far more efficient.
>
> [root] 16:02 [~] time cp /var/cache/swapfile here
> `/var/cache/swapfile' -> `here'
>
> real 0m37.904s
> user 0m0.115s
> sys 0m13.033s

size of this file?

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