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:[EMAIL PROTECTED] > > 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 > > -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
