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

[Mark Seger]

Michael S. Tsirkin wrote:

>Quoting r. Grant Grundler <iod00d at hp.com>:
>  
>
>>Subject: Re: performance counters in /sys
>>
>>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