Hi all
I understand that the C implementation of Python use a global interpreter
lock to avoid problems, so doing CPU bound tasks in multiple threads
will not result in better performance on multi-CPU systems.
However, I assumed that calls to (thread safe) C Library functions
release the global interpreter lock.
Today I checked the performance of some slow re.match() calls and found,
that the do not run in parallel on a multi-CPU system.
1) Is there a reason for this?
2) Is the regex library not thread-safe?
3) Is it possible, to release the GIL in re.match() to
get more performance?
I'm using Python 2.5
Thanks for your help
Mirko
--
"I've found that people who are great at something are not so much
convinced of their own greatness as mystified at why everyone else seems
so incompetent."
Paul Graham in "Great Hackers"
4  1339 
In article <sl********************************@dziadzka.de> ,
Mirko Dziadzka <mi************@gmail.comwrote:
>
I understand that the C implementation of Python use a global interpreter
lock to avoid problems, so doing CPU bound tasks in multiple threads
will not result in better performance on multi-CPU systems.
However, I assumed that calls to (thread safe) C Library functions
release the global interpreter lock.
Generally speaking that only applies to I/O calls.
>Today I checked the performance of some slow re.match() calls and found,
that the do not run in parallel on a multi-CPU system.
1) Is there a reason for this?
2) Is the regex library not thread-safe?
3) Is it possible, to release the GIL in re.match() to
get more performance?
Theoretically possible, but the usual rule applies: patches welcome
--
Aahz (aa**@pythoncraft.com) <* http://www.pythoncraft.com/
"as long as we like the same operating system, things are cool." --piranha
On Jun 25, 9:05*am, Mirko Dziadzka <mirko.dziad...@gmail.comwrote:
>
1) Is there a reason for this?
I think it is because the Python re library uses the Python C-API
which is not threadsafe.
2) Is the regex library not thread-safe?
3) Is it possible, to release the GIL in re.match() to
* *get more performance?
However, I assumed that calls to (thread safe) C Library functions
release the global interpreter lock.
This is mainly applicable to external C libraries. The interface to
them may not be thread-safe; anything that uses the Python API to
create/manage Python objects will require use of the GIL. So the
actual regex search may release the GIL, but the storing of results
(and possibly intermediate results) would not. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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