FreeBSD 7.1 taskq em performance

Ray Kinsella raykinsella78 at
Mon Apr 27 08:43:45 UTC 2009


I would recommend that you start with PMCStat and figure where the
bottleneck is,
Given that you have a two threads and your CPU is at 100%,
my a apriori guess would be a contention for a spinlock,
so I might also try to use LOCK_PROFILING to handle on this.


Ray Kinsella

On Fri, Apr 24, 2009 at 11:42 PM, Joseph Kuan <kuan.joe at> wrote:

> Hi all,
>  I have been hitting some barrier with FreeBSD 7.1 network performance. I
> have written an application which contains two kernel threads that takes
> mbufs directly from a network interface and forwards to another network
> interface. This idea is to simulate different network environment.
>  I have been using FreeBSD 6.4 amd64 and tested with an Ixia box
> (specialised hardware firing very high packet rate). The PC was a Core2 2.6
> GHz with dual ports Intel PCIE Gigabit network card. It can manage up to
> 1.2
> million pps.
>  I have a higher spec PC with FreeBSD 7.1 amd64 and Quadcore 2.3 GHz and
> PCIE Gigabit network card. The performance can only achieve up to 600k pps.
> I notice the 'taskq em0' and 'taskq em1' is solid 100% CPU but it is not in
> FreeBSD 6.4.
>  Any advice?
>  Many thanks in advance
>  Joe
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