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

On 04/30/2012 02:12 AM, Michael S. Tsirkin wrote:

On Tue, Jun 28, 2011 at 10:19:48AM -0700, Rick Jones wrote:

quoted

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