On 11/12/10 09:05, Paul Eggert wrote: > It seems to me that this code in sort.c: > > unsigned long int np2 = num_processors (NPROC_CURRENT_OVERRIDABLE); > if (!nthreads || nthreads > np2) > nthreads = np2; > > is now obsolete. It was written assuming spin locks, but now that > we use mutexes, shouldn't we respect an explicit --parallel=N > flag? Something like the following, say? This would let the user > override the environment in the command line, which is normally what > people would expect.
Yes I think you're right. Related to this is the default number chosen, which might be best to restrict to 8 or so as there are diminishing returns after that. Of course we'd need to benchmark again with all the recent changes to find an appropriate default. The gcc compile farm has a niagra 32 core (gcc12) and and a magny-cours 24 core (gcc10) available. Also I notice Chen has inadvertently been omitted from THANKS, and that his UCLA email address should probably be added to .mailmap cheers, Pádraig.
