Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:40010
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 66.249.92.169 as permitted sender)
DomainKey-Status: bad
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=from:to:subject:date:user-agent:cc:references:in-reply-to
         :mime-version:content-type:content-transfer-encoding
         :content-disposition:message-id;
        b=QoOXw6kHM0TxC2hlhCKFH/6jb+/rQdJx8kvRNx11UTwMAPH/IQFoCxjiqk4vRNs8Mh
         DidAQlv+AxOgEM70DP3wwiRdQ672TQ32NJ7+qMMVXDq0wTimURhoZi3YF5tC2lOqiK1m
         Tz6ekgw7Gzh+3pC/cwQS7ZAFBbMCAxmkIAel4=
To: Dmitry Stogov <dmitry@zend.com>
Date: Wed, 20 Aug 2008 07:47:07 +0200
User-Agent: KMail/1.10.0 (Linux/2.6.26-noch; KDE/4.1.0; i686; ; )
Cc: PHP Development <internals@lists.php.net>,
 Stanislav Malyshev <stas@zend.com>,
 Andi Gutmans <andi@zend.com>
References: <200808170419.11153.arnaud.lb@gmail.com> <200808190116.04713.arnaud.lb@gmail.com> <48AA74C6.10507@zend.com>
In-Reply-To: <48AA74C6.10507@zend.com>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-ID: <200808200747.07817.arnaud.lb@gmail.com>
Subject: Re: [PHP-DEV] [PATCH] ZTS as fast as non-ZTS
From: arnaud.lb@gmail.com (Arnaud Le Blanc)

Hi,

On Tuesday 19 August 2008 09:22:46 Dmitry Stogov wrote:
> Hi Arnaud,
> 
> Arnaud Le Blanc wrote:
> > Hi,
> > 
> > On Monday 18 August 2008 19:46:46 Dmitry Stogov wrote:
> >> Hi Arnaud,
> >>
> >> The patch looks very interesting.
> >> I think it may be committed to the HEAD in the nearest future.
> >> I don't have time to look into all details in the moment.
> >>
> >> Could you explain why --with-tsrm-full-__thread-tls doesn't work with 
> >> dlopen() however --with-tsrm-__thread-tls does?
> > 
> > That's due to the way TLS works internally. Actually I need further 
reading on 
> > that.
> 
> I don't see a big difference between --with-tsrm-full-__thread-tls and 
> --with-tsrm-__thread-tls from TLS point of view (may be I miss it), so I 
> don't understand why one works and the other doesn't.

Badly both was not expected to work with dlopen()  :( 
http://marc.info/?l=php-internals&m=121912220705964&w=2

It works when using an other TLS model (which requires PIC).
This model is less efficient but it still improves performance. PIC-patched is 
faster than non-PIC-unpatched, and the improvement is even greater against 
PIC-unpatched.

> 
> The patch looks more difficult for me than it should. I would prefer to 
> have only --with-tsrm-full-__thread-tls, if it works, as the patch would 
> be simple and PHP faster.
> 
> Another simple solution, which you probably already tested, is to use 
> only global __thread-ed tsrm_ls (and don't pass/fetch it), however, 
> access thread-globals in the same way: 
> ((*type)tsrm_ls[global_module_id])->global_fileld

Yes, I tested and it given 4.7s on bench.php (vs 3.8s with the current patch).

> 
> Anyway you did a great job. I would like to see this idea implemented in 
> HEAD. It is little bit late for 5.3 :(
> 
> Thanks. Dmitry.
> 
> >> Did you test the patch with DSO extensions?
> > 
> > I will, but I guess that will be behaves like another shared library 
> > dlopen()ed by Apache.
> > 
> >> It would be interesting to try the same idea on Windows with VC.
> > 
> > I will try too.
> > 
> >> Thanks. Dmitry.
> >>
> >> Arnaud Le Blanc wrote:
> >>> Hi,
> >>>
> >>> Currently the way globals work forces to pass a thread-local-storage 
> > pointer 
> >>> across function calls, which involves some overhead. Also, not all 
> > functions 
> >>> get the pointer as argument and need to use TSRMLS_FETCH(), which is 
slow. 
> > For 
> >>> instance emalloc() involves a TSRMLS_FETCH(). An other overhead is 
> > accessing 
> >>> globals, using multiple pointers in different locations.
> >>>
> >>> The following patch caches each global address in a native TLS variable 
so 
> >>> that accessing a global is as simple as global_name->member. This 
removes 
> > the 
> >>> requirement of passing the tls pointer across function calls, so that 
the 
> > two 
> >>> major overheads of ZTS builds are avoided.
> >>>
> >>> Globals can optionally be declared statically, which speeds up things a 
> > bit.
> >>> Results in bench.php:
> >>> non-ZTS:						3.7s
> >>> ZTS unpatched:					5.2s
> >>> ZTS patched:					4.0s
> >>> ZTS patched and static globals:	3.8s
> >>>
> >>> The patch introduces two new macros: TSRMG_D() (declare) and TSRMG_DH() 
> >>> (declare, for headers) to declare globals, instead of the current 
> > "ts_rsrc_id 
> >>> foo_global_id". These macros declare the global id, plus the __thread 
> > pointer 
> >>> to the global storage.
> >>>
> >>> ts_allocate_id now takes one more callback function as argument to bind 
> > the 
> >>> global pointer to its storage. This callback is declared in TSRMG_D[H]
().
> >>>
> >>> As all TSRMLS_* macros now does nothing, it is needed to call 
> > ts_resource(0) 
> >>> explicitly at least one time in each thread to initialize its storage. A 
> > new 
> >>> TSRMLS_INIT() macro as been added for this purpose.
> >>>
> >>> All this is disabled by default. --with-tsrm-__thread-tls enables the 
> > features 
> >>> of the patch, and --with-tsrm-full-__thread-tls enables static 
declaration 
> > of 
> >>> globals.
> >>>
> >>> It as been tested on Linux compiled with --disable-all in CLI and a bit 
in 
> >>> Apache2 with the worker MPM. Known issues: 
> >>> - Declaring globals statically (--with-tsrm-full-__thread-tls) causes 
> > troubles 
> >>> to dlopen(), actually Apache wont load the module at runtime (it works 
> > with 
> >>> just --with-tsrm-__thread-tls).
> >>> - The patch assumes that all resources are ts_allocate_id()'ed before 
any 
> >>> other thread calls ts_allocate_id or ts_resource_ex(), which is possibly 
> > not 
> >>> the case.
> >>>
> >>> The patch needs some tweaks and does not pretend to be included in any 
> > branch, 
> >>> but I would like to have some comments on it.
> >>>
> >>> The patch: http://arnaud.lb.s3.amazonaws.com/__thread-tls.patch
> >>>
> >>> Regards,
> >>>
> >>> Arnaud
> >>>
> >>>
> > 
> > Regards,
> > 
> > Arnaud
> 

Regards,

Arnaud