On 10/12/2011 10:36 AM, Dag Sverre Seljebotn wrote:
On 10/12/2011 09:55 AM, Robert Bradshaw wrote:
On Sun, Oct 9, 2011 at 5:57 AM, Dag Sverre Seljebotn
<d.s.seljeb...@astro.uio.no> wrote:
On 10/09/2011 02:18 PM, Dag Sverre Seljebotn wrote:
On 10/09/2011 02:11 PM, mark florisson wrote:
with parallel.critical():
this section of code is mutually exclusive with other critical
sections
optional keyword argument 'name' specifies a name for the critical
section,
which means all sections with that name will exclude each other,
but not
critical sections with different names
Note: all threads that encounter the section will execute it, just
not at the same time
On critical sections, I do feel string naming is rather un-Pythonic. I'd
rather have
lock_a = parallel.Mutex()
lock_b = parallel.Mutex()
with cython.parallel:
with lock_a:
...
with lock_b:
...
This maps well to pthread mutexes, though much harder to map it to OpenMP...
So my proposal is:
a) parallel.Mutex() can take a string argument and then returns the
same mutex each time for the same string, meaning you can do
with parallel.Mutex("somename"):
which maps directly to OpenMP.
b) However, this does not make sense:
with parallel.Mutex():
because each thread would instantiate a *seperate* mutex. So raise
compiler error ("Redundant code, thread will never block on fresh mutex")
c) However, one can use a default global Mutex instance:
with parallel.global_mutex
(mapping to an un-named critical in OpenMP)
This seems to be simple enough to implement, and allows generalizing to
the advanced case above later (probably using pthreads/Windows directly).
Dag Sverre
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