[openib-general] Re: performance counters in /sys

[Michael S. Tsirkin]

Quoting r. Mark Seger <Mark.Seger at hp.com>:
> > Quoting r. Grant Grundler <iod00d at hp.com>:
> > 
> > >On Fri, May 20, 2005 at 10:20:29AM -0600, Ronald G. Minnich wrote:
> > >   
> > >
> > > > yes, that is the accepted thing nowadays. And, boy, is it SLOW. SLOW,
> > > > SLOW, SLOW.
> > > > Open file, read ONE value, close file. Takes a long time. So we've seen 
> > > > that for a number of values you really can't sample at interesting 
> > > > rates. 
> > > >
> > >
> > > Exactly. That's Mark's gripe too.
>
> I guess the thing that has me mystified about all this is I can 
> certainly appreciate the potential 'goodness' of having 1 var/file for 
> user oriented access but perhaps one of the better examples of why this 
> is just a bad idea for programmatic access is the individual process 
> stats.  Is the implication of this that some day those too would be 
> moved to /sys as one stat per file?!?  Can you imaging trying to run top 
> or ps if that were to happen?
> 
> -mark

Does someone care enough to post a benchmark?

-- 
MST - Michael S. Tsirkin