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Date: Tue, 29 Jan 2013 14:01:45 +0100
Message-ID: <CAGsPR65E-RFsApVYG_seAUj8v8oUtyh97kKV7mo0g+Kt-2NvNA@mail.gmail.com>
To: Zeev Suraski <zeev@zend.com>
Cc: Pierre Joye <pierre.php@gmail.com>, =?ISO-8859-1?Q?Johannes_Schl=FCter?= <johannes@schlueters.de>, 
	PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] ZTS - why are you using it?
From: damian@tylczynski.pl (=?ISO-8859-2?Q?Damian_Tylczy=F1ski?=)

As a developer I really enjoyed that discussion, it was very
informative for me. I'm always stuck with question which version of
PHP to use.

2013/1/29 Zeev Suraski <zeev@zend.com>:
>> -----Original Message-----
>> From: Pierre Joye [mailto:pierre.php@gmail.com]
>> Sent: Tuesday, January 29, 2013 2:19 PM
>> To: Zeev Suraski
>> Cc: Johannes Schl=FCter; PHP internals
>> Subject: Re: [PHP-DEV] ZTS - why are you using it?
>>
>> On Tue, Jan 29, 2013 at 1:06 PM, Zeev Suraski <zeev@zend.com> wrote:
>>
>> >> It is inter process sharing and is very expensive, nothing to compare
>> > with shared
>> >> memory within a single process, accross many threads.
>> >
>> > What are you basing that assertion on?  Shared memory should have
>> > identical performance to regular process memory.  It's mapped in very
>> > similar way.
>>
>> Testing maybe?
>
> Retest then, you've got it wrong.  Shared memory (or memory mapped files
> as they'd be on Windows) are simply memory, it's available to the process
> in exactly the same way and while the OS does slightly different
> book-keeping for it in how it populates the pages - it's negligible.
>
>> >> >> Miss the rest of my mail or? Current implementation is outdated
>> >> >> and slow.
>> >> >
>> >> > That is true. Many modern compilers and environments provide
>> >> > better support for thread local storages ....
>> >>
>> >> Exactly, or more exactly CRTs (libc, crt and the likes)>
>> >
>> > Can we stop arguing about the implementation
>>
>> No, we can't. The main reason of the bugs and performance issue is due
> to the
>> current implementation and how extensions developers have to deal with
> it. It is
>> not separable from discussing what could be the worst decision we ever
> made,
>> droping thread safety.
>
> Well, I'm not interested in discussing the implementation when the need
> isn't clear to me.
> For example, you could say that thread-safe PHP would be 2x faster.  Or 2=
x
> more memory efficient.  Or will enable us to do XYZ which we otherwise
> can't.
> For now, an *utopian* ZTS mode would, at best, not give us anything.
> Even if we put aside the performance/reliability issues - why would
> someone want that mode over other modes?
>
>> > So far the only real use case that was brought up was for using
>> > pthreads in a long-running app.  I've yet to hear about a single real
>> > reason of why someone would want to use it in web server context that
>> > is not based on misconceptions or myths.
>>
>> Thanks, it is really nice to say something and being told that what has
> been done
>> is misconceptions or myths, especially if you gave up on thread safety
> years ago
>> within your company. That's all good, as long as it only affects your
> company
>> products and not PHP as a whole.
>
> Pierre, I'm sorry, but when you state something like '[shared memory] is
> inter process sharing and is very expensive', there's no other way to
> describe it other than a myth.  Better theoretical performance is a
> misconception.  The best PHP performance/density available today is on
> nginx, which couldn't be farther away from
> multithreaded-PHP-in-process-arch.
>
> Even after what you just said, you've yet to bring up a single reason for
> why one would want to use ZTS inside a web server context.  You seem to
> love ZTS with a vengeance but you can't quite explain why.  My 'company'
> didn't decide anything regarding ZTS.  It was me, probably the person wit=
h
> the most experience with ZTS back in the day, and it was probably much
> more difficult for me than anybody else to realize that the ZTS approach
> was the wrong path to go to as it was my baby project.
>
> BTW, for the love of [insert here], I'm not talking about killing thread
> safety.  It's useful for long running processes, and who knows, maybe in
> the future we'll have threads inside PHP.  But I *am* talking about
> telling people that using ZTS in production is not recommended and that
> they should be using FastCGI instead.
>
> Zeev
>
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>



--=20
Pozdrawiam,
Damian Tylczy=F1ski