Re: getting host CPU utilization (was Re: [PATCH V7 2/4 net-next]skbuff: Add userspace zero-copy buffers in skb)

[Rick Jones]

On 04/30/2012 02:12 AM, Michael S. Tsirkin wrote:
> On Tue, Jun 28, 2011 at 10:19:48AM -0700, Rick Jones wrote:
> > one of these days I'll have to find a good way to get accurate
> > overall CPU utilization from within a guest and teach netperf about
> > it.
>
> I think the cleanest way would be to run another netperf server on the
> host.  netperf would get a flag with host address and get cpu
> utilization info.
>
> This is what we currently do manually: run mpstat on the host.
>
> Thoughts?

I might be able to enhance the LOC_CPU/REM_CPU calibration tests to be 
bona fide CPU utilization tests.

> By the way, could you point me to code used by netperf
> to measure CPU utilization on Linux? I'd like to figure
> out why isn't the result always consistent with e.g. mpstat.

That would be src/netcpu_procstat.c .  That code is automagically 
selected by the configure script when it determines the compilation is 
happening under Linux.  You can, if you wish, manually set it though I 
suspect the only other mechanism known to netperf that would function 
under Linux is the "looper" (aka CPU soaker) method.

rick
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