[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [coreutils] draft [PATCH] sort: explicit --parallel=N now overrides

From: Pádraig Brady
Subject: Re: [coreutils] draft [PATCH] sort: explicit --parallel=N now overrides environment
Date: Sat, 11 Dec 2010 09:46:56 +0000
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/20100227 Thunderbird/3.0.3

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


reply via email to

[Prev in Thread] Current Thread [Next in Thread]