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To: "Kalle Sommer Nielsen" <terrorkalle@gmail.com>
Date: Thu, 21 Aug 2008 14:33:41 +0200
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Cc: Internals <internals@lists.php.net>
References: <200808170419.11153.arnaud.lb@gmail.com> <200808200756.13384.arnaud.lb@gmail.com> <1d03a06c0808201251x55d681cyb20ccf00731bf29f@mail.gmail.com>
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Message-ID: <200808211433.42111.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 Wednesday 20 August 2008 21:51:05 Kalle Sommer Nielsen wrote:
> 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.

Thanks, I didn't known that. I did not have a Professional version of Windows 
but I will try to get one.

> 
> >>
> >> 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
> 

Regards,

Arnaud