[openib-general] performance counters in /sys

[Grant Grundler]

On Fri, May 20, 2005 at 07:25:58AM -0400, Mark Seger wrote:
> I didn't realize some counters are optional.  That kind of blows my 
> notion of a fixed format, space separated output.  8-(

Not entirely. One could fill unimplemented values with -1 or 0.

> Perhaps a better way to focus this conversation is to see what the 
> general feeling is towards statistics that are more oriented towards 
> consumption by programs rather than humans and then discuss the details 
> of format if some consensus can be reached.  I'm also wondering if data 
> is to be combined for mulitple hcas/ports it may make more sense to put 
> it into /proc where those types of structures appear, but that level of 
> discussion should probably also be deferred.

I think the general trend is to move away from /proc.

For monitoring performance, a single /sys file that lists all devices
is the lightest weight and is acceptable according to
Documentation/filesystems/sysfs.txt:

| Attributes should be ASCII text files, preferably with only one value
| per file. It is noted that it may not be efficient to contain only
| value per file, so it is socially acceptable to express an array of
| values of the same type.

Hrm...this means we'd still need 16+ arrays...not much of an improvement.
Any other thoughts?

grant