Re: [Matplotlib-users] matplotlib threadsafe?
Eric Firing wrote: Out of interest, how does one tell MPL to start a new figure and forget everything that's gone before? You can minimize the amount of package and module-level state information by using the oo interface: see examples/agg_oo.py. I tried this example, and it generates no output. Is that to be expected? cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
Chris Withers wrote: Eric Firing wrote: Out of interest, how does one tell MPL to start a new figure and forget everything that's gone before? You can minimize the amount of package and module-level state information by using the oo interface: see examples/agg_oo.py. I tried this example, and it generates no output. Is that to be expected? Chris, It should produce a test.png; it is using a non-interactive backend. It works on my machine. Eric cheers, Chris - This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
Out of interest, how does one tell MPL to start a new figure and forget everything that's gone before? You can minimize the amount of package and module-level state information by using the oo interface: see examples/agg_oo.py. If you change any rcParams dictionary entries, typically using the rc function, then you can restore the dictionary to its default condition with the rcdefaults() function. Eric - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
On Fri, Mar 21, 2008 at 1:40 AM, Eric Firing [EMAIL PROTECTED] wrote: Out of interest, how does one tell MPL to start a new figure and forget everything that's gone before? You can minimize the amount of package and module-level state information by using the oo interface: see examples/agg_oo.py. If you change any rcParams dictionary entries, typically using the rc function, then you can restore the dictionary to its default condition with the rcdefaults() function. I think it is comparatively rare to modify rc params within code (and never necessary since you can achieve the same by setting properties directly using the API) so if the rc params are the only global information we are using (and I am not aware of other problems off the top of my head but you might be well served to post to the antigrain mailing list to see if agg is thread safe) it shouldn't pose a serious problem. JDH - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
Michael Droettboom wrote: At least the Agg backend *looks* to be reasonably threadsafe -- there are no obvious gotchas like global variables etc. Note, though, that multithreading may not gain much in the way of performance since the global interpreter lock is never released around long-running C blocks. It's not performance I'm looking for, it's making sure that MPL apps served from multi-threaded wsgi servers don't screw each others charts up ;-) cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
Eric Firing wrote: In general, I don't think mpl is threadsafe at all; it uses global variables, such as all the rc parameters, that could easily be modified by one thread while being used by another. Yep, I guessed as much, BFL it is then ;-) I think that great care would be needed if one wanted to have multiple threads making plots. Having one plotting thread and any number of threads doing other things, however, should be OK. Out of interest, how does one tell MPL to start a new figure and forget everything that's gone before? At the very least, I think we would have to take all the global state information and put it in a class instance, so there could be multiple plotting machines. Yes. cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
Eric Firing wrote: In general, I don't think mpl is threadsafe at all; it uses global variables, such as all the rc parameters, that could easily be modified by one thread while being used by another. I think that great care would be needed if one wanted to have multiple threads making plots. Having one plotting thread and any number of threads doing other things, however, should be OK. Oh yes -- I didn't think of the rcParams. Michael Droettboom wrote: At least the Agg backend *looks* to be reasonably threadsafe -- there are no obvious gotchas like global variables etc. Note, though, that multithreading may not gain much in the way of performance since the global interpreter lock is never released around long-running C blocks. Possibly this could be changed. The danger would be accidentally modifying or deleting an array that is being used by C extension code. Modifying may be problematic, but deleting would not be likely -- the C function holds a reference to each of the arrays as they are using them. However, I can't speak about this from any experience -- so, maybe it needs some trying. Any patches to help with thread safety and performance are of course welcome ;) At the very least, I think we would have to take all the global state information and put it in a class instance, so there could be multiple plotting machines. Pyplot would then instantiate and use one of these; the OO API would allow one to instantiate any number of them. I have not thought about how easy or hard this would be. Ditto that. Having just come back from PyCon, I'll parrot the standard Python answer to this question which is: Don't use threads, use multiple processes, which would seem to solve all these issues -- but, I understand that it not always the best solution. Mike Eric Cheers, Mike Chris Withers wrote: Hi All, I'm wondering what work people have done with matplotlib in multi-threaded environments such as your average python web framework. Is matplotlib threadsafe? How have people gone about safely using it in a multi-threaded environment? cheers, Chris - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- Michael Droettboom Science Software Branch Operations and Engineering Division Space Telescope Science Institute Operated by AURA for NASA - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
At least the Agg backend *looks* to be reasonably threadsafe -- there are no obvious gotchas like global variables etc. Note, though, that multithreading may not gain much in the way of performance since the global interpreter lock is never released around long-running C blocks. However, I can't speak about this from any experience -- so, maybe it needs some trying. Any patches to help with thread safety and performance are of course welcome ;) Cheers, Mike Chris Withers wrote: Hi All, I'm wondering what work people have done with matplotlib in multi-threaded environments such as your average python web framework. Is matplotlib threadsafe? How have people gone about safely using it in a multi-threaded environment? cheers, Chris - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib threadsafe?
In general, I don't think mpl is threadsafe at all; it uses global variables, such as all the rc parameters, that could easily be modified by one thread while being used by another. I think that great care would be needed if one wanted to have multiple threads making plots. Having one plotting thread and any number of threads doing other things, however, should be OK. Michael Droettboom wrote: At least the Agg backend *looks* to be reasonably threadsafe -- there are no obvious gotchas like global variables etc. Note, though, that multithreading may not gain much in the way of performance since the global interpreter lock is never released around long-running C blocks. Possibly this could be changed. The danger would be accidentally modifying or deleting an array that is being used by C extension code. However, I can't speak about this from any experience -- so, maybe it needs some trying. Any patches to help with thread safety and performance are of course welcome ;) At the very least, I think we would have to take all the global state information and put it in a class instance, so there could be multiple plotting machines. Pyplot would then instantiate and use one of these; the OO API would allow one to instantiate any number of them. I have not thought about how easy or hard this would be. Eric Cheers, Mike Chris Withers wrote: Hi All, I'm wondering what work people have done with matplotlib in multi-threaded environments such as your average python web framework. Is matplotlib threadsafe? How have people gone about safely using it in a multi-threaded environment? cheers, Chris - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
