Re: Apache + mod_php performance

On 9/25/24 4:17 PM, Arne Vajhøj wrote:

On 9/25/2024 5:10 PM, Arne Vajhøj wrote:

Apache on VMS is prefork MPM. Yuck.

 Which puzzles me.
 VMS is a threading OS not a forking OS.

Preforking in Apache just means it creates subprocesses at start-up
time.  Whoever invented the term apparently thought fork() was the only
way to create a subprocess.  On VMS it will obviously use LIB$SPAWN or
SYS$CREPRC.

And prefork MPM is really an early 90's traditional Unix design.
 Using worker MPM on VMS would make more sense IMHO.

That requires everything running in each MPM process to be thread-safe.
It also probably doesn't provide the scaling advantages on VMS that it
would on unixen because there is no pthread_sigsetmask: all signals are
delivered in the main thread. Which means that somewhere around where
threads could provide a scaling advantage, the main thread will get
saturated and the advantage disappears. This based on the assumption
that signals would be used for things like asynchronous I/O completion;
I don't really know that for sure, but it seems like a pretty safe
assumption.

The best would probably have been to create a VMS MPM
based on the WinNT MPM.

And all of the Apache extensions would have to be rewritten to use QIOs
and ASTs?  That's a pretty big ask.