Re: [patch] procfs/procps threading performance speedup, 2.5.62

["Albert D. Cahalan" <acahalan@cs.uml.edu>]

> Albert, do you realize the simple fact that the procps
> enhancements we did change absolutely nothing for the 'ps m'
> case? All thread PIDs are still scanned and sorted.

That is a contradiction. There is no sorting with "ps m".
Any ordering is from the /proc directory itself.

Sorting is not default because of the memory requirements
and because there have been many kernel bugs that cause
ps to hang when it hits a particular process. Sorting may
mean that ps hangs or is killed before producing anything.

> And mind you, thread-directories do not change much in
> this area - the PIDs within the thread-directory will
> still be largely unsorted, and it will not make the
> reading & sorting of 20K threads any faster.

That's OK. I need in-kernel grouping, not in-kernel sorting.
It's fine to mix up thread order, but bad to interleave the
threads of unrelated processes.

> so in fact _i_ came up with this whole issue 7 months ago. I just dont
> share many of _your_ largely bogus arguments that seem to miss the point.  
> Can we finally stop this storm in a teapot?

Glad to, assuming you understand the importance of grouping.
I hope I have now done a better job of explaining it.