Re: ZTS performance

From:	Zeev Suraski	Date:	Tue, 25 Mar 2003 08:28:48 +0000
Subject:	Re: ZTS performance
References:	1 2	Groups:	php.internals
Request:	Send a blank email to internals+get-248@lists.php.net to get a copy of this message

At 22:25 24/03/2003, Sascha Schumann wrote:

That's one of the reasons, I would guess. The libc memory manager is not very efficient with multiple threads accessing it at once, it has locks (which is one of the reasons we implemented our own in ZE2). It's definitely one of the reasons, and as you know, performance penalties accumulate.
    Which libc are you referring to here?

All, basically. Even the ultra optimized Windows memory manager is inefficient when it comes to simultaneous allocations in multiple threads, when compared to having different heaps for different threads.

    Today's Linuxthreads implementation uses a very simple
    mechanism to maintain TLS (calculating an object's address in
    software) whereas NPTL will shift this work to the
    processor's MMU.  I expect a big win for PHP's thread-safe
    mode.

That's what Windows TLS does, IIRC.

    This positive effect will be automatically achieved by
    continuing our use of POSIX APIs.

No surprise there... Zeev