Re: [PATCH] ZTS as fast as non-ZTS

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. > > 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.patchGL > > y
v46¶„>€ > > > > Regards, > > > > Arnaud > > > > > Regards, Arnaud