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Re: [glibc] Fix Linux sysconf(_SC_NPROCESSORS_[CONF|ONLN])performance problem


On Thu, Jun 16, 2011 at 11:17 AM, Ulrich Drepper <drepper@gmail.com> wrote:
>
> I would be happy to use any new interface to get to this information
> more quickly.

And I'd be happy to discuss it once the glibc implementation isn't crap.

It works both ways, guys.  I'm not interested in bending over
backwards for glibc that doesn't even bother to do a reasonable job
using the current interfaces

You can argue about "you shouldn't cache" all you want, but you can't
actually point to anything that cares, can you? In contrast, I can
point to real programs that really care about the performance issue.

And then when I make bug reports against glibc about real-world issues
(memcpy behavior), you talk about performance issues that aren't even
real.

You can't have it both ways, guys. Why do you care about some
imaginary cycles in memcpy (when I can point to actual user programs
that BREAK due to glibc changes), but then when I point to actual real
performance data, you don't care at all and talk about some breakage
with nothing to actually back that up.

Performance is a real issue, and has real semantics too. NOBODY cares
about some theoretical CPU hotplug event.

                        Linus


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