Hi Anatol, I didn't completely get your ideas, but if tsrm_ls_cache can't be exported on Windows directly, can we have a copy of tsrm_ls_cache in each DLL/EXE and initialize it once?
Thanks. Dmitry. On Sun, Sep 21, 2014 at 9:19 PM, Anatol Belski <anatol....@belski.net> wrote: > Hi Dmitry, > > On Sat, September 20, 2014 09:58, Anatol Belski wrote: > > Hi Dmitry, > > > > > > On Fri, September 19, 2014 12:43, Dmitry Stogov wrote: > > > >> I know :) > >> Interned strings in PHP5 were implemented as characters allocated in one > >> single buffer. Adding new strings into this buffer from different > >> threads would require synchronization (locks). > >> > >> In PHP7 this implementation was changed. So it's probably must be > >> possible to use interned strings in ZTS now. If we use separate > >> HashTables > >> for interned strings in different threads we may share some common part > >> of predefined interned strings and have new interned strings in each > >> thread independently. I'm not sure if it'll work well with opcache, > >> because it substitutes interned strings handling mechanism to use shared > >> memory. May be it'll work out of the box. BTW: I'm not interested in > >> implementing this myself. > >> > >> Also, if we really like ZTS, may be PHP7 is the time to switch to > >> native TLS and remove all these TSRMLS macros. > >> Even if it won't allow to run ZTS on some platforms, it won't be the end > >> of the world, because ZTS is not really widely used now. I won't be > >> able to work on it actively, but I may provide some help. > >> > >> Thanks. Dmitry. > >> > >> > > maybe it'd make sense to do it the other way round. First get rid of > > TSRM, > > than look what is doable with interned strings? I'd be sure in the game, > if > > there are enough interested people to actively do that. > > > yesterday Joe pushed the approach on the TSRMLS_* removal subject > > http://git.php.net/?p=php-src.git;a=shortlog;h=refs/heads/native-tls > > While trying to port it for Windows, I see some design issues and have an > idea how to solve it. The patch is relying on a few things which Visual > Studio cannot handle. The first one: > > TSRM_API extern TSRM_TLS void *tsrm_ls_cache; > > but exporting the TSRM cache from a DLL won't work with VS. There it would > look like > > __declspec(dllexport) extern __declspec(thread) void *tsrm_ls_cache; > > VS linker cannot share variables directly between DLL and EXE. > Furthermore, even bigger issue could be with modules loaded on runtime. > > The second issue is that while ini entries are defined in static arrays, > when they link to some SAPI or extension globals, they would have an id > passed. That Id would be declared like > > __declspec(dllimport) ts_rsrc_id cli_server_globals_id; > > While passed to the ini entry by reference, it's still not a constant > value. So VS refuses to initialize an ini entry with something not from > the constant extent (AFAIK that's ok for C89). > > > That's for the issues. How to solve them - after some research it looks > like one can share thread data using getter/setter functions (using > DLL_THREAD_ATTACH event in DllMain to initialize current thread data). > That would probably require some more rewrites in the code. The main > question, whether the negative impact because of having to do the extra > function calls would make such porting senseless. > > The flow were like > > apache (or php) binary starts thread > TSRM layer inits TLS data > php inits globals / depend on TSRM layer > extensions init/read globals / depend on TSRM layer > > That's just a basic idea yet. > > > For the second issue - some similar approach. Instead of using > &some_globals_id, one could replace it with a function pointer so then it > can deliver the right location by thread. > > What do you think about my solution ideas? Maybe also there was some other > approaches we didn't take in account yet? Depending on whether we can use > the function calls, maybe it'd even make sense to make something like > libtsrm to incapsulate all the TS features. > > Thanks > > Anatol > > > > > >
