Re: [PATCH 2/3] powerpc: Instrument Hypervisor Calls: add wrappers

On Fri, Jul 14, 2006 at 07:15:45PM -0500, Nathan Lynch wrote:

Hmm, isn't it possible that the stats could be corrupted if we process
an interrupt/softirq which does an hcall while the stats are being
updated?  Maybe it's not a show-stopper, but it seems to me that
accuracy could suffer under some workloads.

Yes, they can become inaccurate.  Is this what you mean by 'corrupted' or
you thinking of something worse?

There is going to be a trade off between accuracy and the overhead of the
data gathering.  What really needs to happen is some good benchmarking to
measure the costs of different approaches.  I'm pretty sure I can get
someone to provide such data.

In this patch, I have minimized the overhead in data collection at the
cost of accuracy.

-- 
Mike