Re: [PHP-DEV] thread safety for binding issues
Bless You! It still segfaults all over the place (which is another story), but that particular call_user_function() now works, thanks :) and happy easter egg searching ;) - Markus On Sun, Mar 31, 2002 at 01:11:27PM +0300, Zeev Suraski wrote : At 20:59 30/03/2002, Markus Fischer wrote: Yes, exactly. Ok, in that case, by default this won't work 'very nicely' with PHP (because it's not very standard), but you should be able to get it to work relatively easily. The problem: All of PHP's resources (globals, memory management, resource lists, basically everything) are locked to a specific thread. If you use all of the standard macros (TSRMLS_FETCH(), TSRMLS_DC, etc.) then your code lives entirely within the thread in which it's running, and cannot access anything from other threads. The solution: If you need to manipulate resources of another thread, you can do so, but you have to do a bit of hacking on your own. 1. When you register the callback, you have to remember which thread you'd want to interface with when the callback is called. You can obtain the thread id by using tsrm_thread_id(): THREAD_T thread_id = tsrm_thread_id(); You have to store this information in a place which would be later accessible from the callback. 2. inside the callback, don't use TSRMLS_FETCH(). Instead, use the following line of code: void ***tsrm_ls = (void ***) ts_resource_ex(0, thread_id); 3. It's important to remember that there are some things that you must not do inside your callback, due to mutual exclusion problems. For instance, doing any 'writes' to the resource lists, or even the memory manager - is likely to cause a crash due to race conditions with the thread that owns these resources. As long as you limit yourself to read-only data, it should be fine (even though I don't think we ever made sure that the data structures are safe for reading while another thread writes to them). That's about all I can tell you, other than good luck, and don't do it unless you really have to :) Zeev -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Yes, thanks for the answer. I think the problem is just that I mixed up two different things (thread-safety vs. multi-threaded). Err .. any idea if/when PHP itself will get MTed ? :) - Markus On Sat, Mar 30, 2002 at 09:14:56AM +0200, Zeev Suraski wrote : It should work, it's using exactly the same thread safe code as the one under Windows... Zeev At 14:14 29/03/2002, Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Get MT'd? What do you mean by that? We have no plans to make PHP a multithreaded application at any time in the future, but I'm not exactly sure why it matters to you..? Zeev At 17:16 30/03/2002, Markus Fischer wrote: Yes, thanks for the answer. I think the problem is just that I mixed up two different things (thread-safety vs. multi-threaded). Err .. any idea if/when PHP itself will get MTed ? :) - Markus On Sat, Mar 30, 2002 at 09:14:56AM +0200, Zeev Suraski wrote : It should work, it's using exactly the same thread safe code as the one under Windows... Zeev At 14:14 29/03/2002, Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
My understanding from Markus' original email was that the library he is using calls back into php on a different thread than that which he called it with. Shane Zeev Suraski wrote: Get MT'd? What do you mean by that? We have no plans to make PHP a multithreaded application at any time in the future, but I'm not exactly sure why it matters to you..? Zeev At 17:16 30/03/2002, Markus Fischer wrote: Yes, thanks for the answer. I think the problem is just that I mixed up two different things (thread-safety vs. multi-threaded). Err .. any idea if/when PHP itself will get MTed ? :) - Markus On Sat, Mar 30, 2002 at 09:14:56AM +0200, Zeev Suraski wrote : It should work, it's using exactly the same thread safe code as the one under Windows... Zeev At 14:14 29/03/2002, Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Markus - is that what you're talking about..? Zeev At 20:37 30/03/2002, Shane Caraveo wrote: My understanding from Markus' original email was that the library he is using calls back into php on a different thread than that which he called it with. Shane -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Yes, exactly. On Sun, Mar 31, 2002 at 12:48:04AM +0300, Zeev Suraski wrote : Markus - is that what you're talking about..? Zeev At 20:37 30/03/2002, Shane Caraveo wrote: My understanding from Markus' original email was that the library he is using calls back into php on a different thread than that which he called it with. Shane -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
At 20:59 30/03/2002, Markus Fischer wrote: Yes, exactly. Ok, in that case, by default this won't work 'very nicely' with PHP (because it's not very standard), but you should be able to get it to work relatively easily. The problem: All of PHP's resources (globals, memory management, resource lists, basically everything) are locked to a specific thread. If you use all of the standard macros (TSRMLS_FETCH(), TSRMLS_DC, etc.) then your code lives entirely within the thread in which it's running, and cannot access anything from other threads. The solution: If you need to manipulate resources of another thread, you can do so, but you have to do a bit of hacking on your own. 1. When you register the callback, you have to remember which thread you'd want to interface with when the callback is called. You can obtain the thread id by using tsrm_thread_id(): THREAD_T thread_id = tsrm_thread_id(); You have to store this information in a place which would be later accessible from the callback. 2. inside the callback, don't use TSRMLS_FETCH(). Instead, use the following line of code: void ***tsrm_ls = (void ***) ts_resource_ex(0, thread_id); 3. It's important to remember that there are some things that you must not do inside your callback, due to mutual exclusion problems. For instance, doing any 'writes' to the resource lists, or even the memory manager - is likely to cause a crash due to race conditions with the thread that owns these resources. As long as you limit yourself to read-only data, it should be fine (even though I don't think we ever made sure that the data structures are safe for reading while another thread writes to them). That's about all I can tell you, other than good luck, and don't do it unless you really have to :) Zeev -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus PHP is thread safe, not multi-threaded. ie. scripts cannot be multi-threaded. You will have to somehow proxy the data back to the original calling thread for your library to work. Shane -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
On Fri, Mar 29, 2002 at 09:14:46AM -0800, Shane Caraveo wrote : Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus PHP is thread safe, not multi-threaded. ie. scripts cannot be multi-threaded. You will have to somehow proxy the data back to the original calling thread for your library to work. Ah, understood. So, the short answer would be it was by own stupidity ;-) About proxying the data .. you don't happen to have some more description or resource how to accomplish this before I try to reinvent the wheel ? thanks. - Markus -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
Markus Fischer wrote: On Fri, Mar 29, 2002 at 09:14:46AM -0800, Shane Caraveo wrote : Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus PHP is thread safe, not multi-threaded. ie. scripts cannot be multi-threaded. You will have to somehow proxy the data back to the original calling thread for your library to work. Ah, understood. So, the short answer would be it was by own stupidity ;-) About proxying the data .. you don't happen to have some more description or resource how to accomplish this before I try to reinvent the wheel ? thanks. - Markus You'll probably be able to get away with using condition variables, but it's too much to describe, and I haven't done much pthreads stuff. You could get the o'reilly pthreads book for reference, or dig around for exampls on the net. Shane -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] thread safety for binding issues
It should work, it's using exactly the same thread safe code as the one under Windows... Zeev At 14:14 29/03/2002, Markus Fischer wrote: Hi, how much thread-safe is PHP on linux when compiled with --enable-experimental-zts ? When I a set up a callback handler for a 3rd library which uses threads and in this (C) callback I call call_user_function() (to provide custom callbacks) - bang , I get a segfault. Should it work and I'm doing something stupid or is this some limitation? Hints? - Markus -- Please always Cc to me when replying to me on the lists. GnuPG Key: http://guru.josefine.at/~mfischer/C2272BD0.asc Mind if I MFH ? What QA did you do on it? the usual? ah... none :) -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
