Hello, Launch a Python interactive session. Don't do anything special, just launch it. Look at the memory usage of this process (e.g. `ps aux | grep python`). The process takes about 4 MB.
Then, just type : >>> import tg Just that. Nothing else. No application modules or data. Look at the process size again. Here it is 28 MB /just for having imported TurboGears/. (your mileage may vary) Now consider that under e.g. a mod_wsgi setup, every worker thread will have a separate interpreter (so that there is true isolation). It means that those 28 MB won't be shared, because they are comprised of objects (dicts, strings, tuples, functions, etc.) which are created dynamically when importing the modules (yes, it is different from what e.g. C shared libraries work). If your mod_wsgi setup has instantiated 8 worker threads, it will already take more than 220 MB wthout any application-specific stuff thrown into the mix. (the default value for the `threads` parameter of a mod_wsgi daemon process is 15... I'll let you do the math) This shows some of the problems associated with the TurboGears approach of "re-use every third-party module under the sun". If you suddenly find out that your mod_wsgi daemon process bubbles to 300MB+ values, no, there isn't necessarily a memory leak in your Web application. You are just using TurboGears :-) Regards Antoine. PS : those numbers are taken on a 64-bit setup. A 32-bit build of Python would show significantly smaller numbers, due to the smaller pointer (and C long) size. PPS : the cost of a single garbage collection then becomes quite funny to watch, too: - before tg is imported: python -m timeit -s "import gc" "gc.collect()" 100 loops, best of 3: 3.05 msec per loop - after tg is imported: python -m timeit -s "import tg, gc" "gc.collect()" 10 loops, best of 3: 61.5 msec per loop --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TurboGears" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/turbogears?hl=en -~----------~----~----~----~------~----~------~--~---
