Justin Erenkrantz <[EMAIL PROTECTED]> writes:
> On Mon, Jul 02, 2001 at 08:21:10AM -0400, Jeff Trawick wrote:
> > Please don't commit just yet.
>
> Should I back this out? Ryan wants to T&R at 10AM PST. I guess the
> easy "fix" would be to place fcntl() decision AFTER the
> pthread_mutex_t support.
Definitely... HP-UX and OS/390 are now broken. The shared memory
mechanism used by the cross-process pthread mutex support doesn't work
on those systems.
> > That piece of code decides not what kind of interprocess lock
> > mechanism APR *has* support for on the platform but what kind of
> > interprocess lock mechanism APR will *use* by default.
>
> Correct, I knew that. But, as seen by the other warning that was
> triggered by this, no one actually has ever tested/maintained this code.
> Now, we can start to exercise it. =-) (Which is partly the reason why
> I was complaining about the 2.0.20 T&R taking in these changes...)
I'd say that the Apache AcceptMutex directive gives you plenty of
ability to exercise it without changing the default lock choice :)
> > I suspect that you misunderstood what that code is doing... otherwise,
> > you'd try to explain why you want to change the [usual] default
> > mechanism from fcntl() to interprocess pthread mutex.
>
> Typically, from my understanding of things, pthread mutex should be
> the option that lets us scale the best on the high-end. From what
> Bill said, this is what IBM ships with IBM HTTPD. And, on Solaris,
> you want to use pthread-related locking for best performance. Now, I
> could be wrong about this being the "best choice."
Basically, I think we changed the Apache default without a crisp
understanding of why it should change. My understanding of things is
that on Solaris and AIX the best lock choice depends on the config of
Apache and the machine. I can't tell you that fcntl is "better
overall" (whatever that means), but I don't see any info to support
the claim that pthread mutex is "better overall" either.
> What platforms are going to have pthread_mutex_t with SHARED_PROCESS
> that WORKS and not have this?
OS/390, HP-UX, dunno what else (if any)
--
Jeff Trawick | [EMAIL PROTECTED] | PGP public key at web site:
http://www.geocities.com/SiliconValley/Park/9289/
Born in Roswell... married an alien...
