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Message-ID: <1d03a06c0808201251x55d681cyb20ccf00731bf29f@mail.gmail.com>
Date: Wed, 20 Aug 2008 21:51:05 +0200
To: "Arnaud Le Blanc" <arnaud.lb@gmail.com>
Cc: Internals <internals@lists.php.net>
In-Reply-To: <200808200756.13384.arnaud.lb@gmail.com>
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References: <200808170419.11153.arnaud.lb@gmail.com>
	 <200808190700.30255.arnaud.lb@gmail.com>
	 <698DE66518E7CA45812BD18E807866CE01E77585@us-ex1.zend.net>
	 <200808200756.13384.arnaud.lb@gmail.com>
Subject: Re: [PHP-DEV] [PATCH] ZTS as fast as non-ZTS
From: terrorkalle@gmail.com ("Kalle Sommer Nielsen")

2008/8/20 Arnaud Le Blanc <arnaud.lb@gmail.com>:
> Hi,
>
> On Tuesday 19 August 2008 18:22:44 Andi Gutmans wrote:
>> OK checked with Zeev. It seems there are some significant limitations at
>> least on Windows including that it doesn't work with LoadLibrary()
>> (which is our bread and butter).
>
> Ok, so there is the same limitations than on Linux with dlopen() :(
>
>> There may also be some size limitations on thread local storage.
>> In any case, this is Windows-only feedback and we may find additional
>> limitations/compatibility issues on other platforms.
>>
>> As there are clear benefits to an increased use of TLS (we already use
>> it for index caching today) I definitely suggest to revisit this issue
>> and try and figure out for the variety of platforms whether there's some
>> middle ground that we can make work. It sounds like a non-trivial
>> project though.
>> Arnaud, are you setup to also play around with Windows and possibly some
>> other OSes to look into this further?
>
> Yes, I will try at least with Windows (XP, so no IIS) and FreeBSD.
>

Windows XP Professional have IIS, all you need is your CD and then
install it from the Add/Remove programs. It's IIS 5.1, which should be
good enough.

>>
>> Andi
>>
>>
>> > -----Original Message-----
>> > From: Arnaud Le Blanc [mailto:arnaud.lb@gmail.com]
>> > Sent: Monday, August 18, 2008 10:00 PM
>> > To: Andi Gutmans
>> > Cc: PHP Development
>> > Subject: Re: [PHP-DEV] [PATCH] ZTS as fast as non-ZTS
>> >
>> > Hi,
>> >
>> > Yes, I have looked for the issue with --with-tsrm-full-__thread-tls
>> and there
>> > are effectively some issues.
>> >
>> > When building PIC code, the used TLS model is a static model which
>> does not
>> > allow modules to be loaded at run-time. glibc's dlopen() sometimes
>> allow such
>> > code to be loaded at runtime when it finds some free memory, that's
>> why --
>> > with-
>> > tsrm-__thread-tls works, but it is not expected to always work.
>> >
>> > So when building PIC code that's expected to work only when the
>> > server/application links the PHP module, or when using LD_PRELOAD,
>> etc.
>> >
>> > Building non-PIC code allows to use a dynamic TLS model, which allows
>> to load
>> > modules a run-time, but it is less efficient (4.8s in bench.php, still
>> faster
>> > than unpatched version, even non-PIC, but less efficient).
>> >
>> > Regards,
>> >
>> > Arnaud
>> >
>> > On Tuesday 19 August 2008 06:18:51 Andi Gutmans wrote:
>> > > Hi Arnaud,
>> > >
>> > > I remember that at the time we looked at thread local storage and
>> there
>> > > were some real issues with it. I can't remember what as it was about
>> 7+
>> > > years ago.
>> > > I will ask Zeev if he remembers and if not search my archives (don't
>> > > have years prior to 2007 indexed :'( ).
>> > >
>> > > Andi
>> > >
>> > >
>> > >
>> > >
>> > > > -----Original Message-----
>> > > > From: Arnaud Le Blanc [mailto:arnaud.lb@gmail.com]
>> > > > Sent: Saturday, August 16, 2008 7:19 PM
>> > > > To: PHP Development
>> > > > Subject: [PHP-DEV] [PATCH] ZTS as fast as non-ZTS
>> > > >
>> > > > 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
>> > > >
>> > > >
>> > > > --
>> > > > PHP Internals - PHP Runtime Development Mailing List
>> > > > To unsubscribe, visit: http://www.php.net/unsub.php
>> > >
>> > >
>>
>>
>
> Regards,
>
> Arnaud
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>



-- 
Kalle Sommer Nielsen