Re: Re: [PATCH] fix threaded grep for machines with only one cpu
- From
Heiko Voigt <hvoigt@hvoigt.net>
- Date
- Feb 16, 2010, 18:02 UTC
- Message-ID
- <20100216180209.GA1532@book.hvoigt.net>
- In-Reply-To
- <7vljetlx8r.fsf@alter.siamese.dyndns.org>
On Mon, Feb 15, 2010 at 06:39:48PM -0800, Junio C Hamano wrote:
> Junio C Hamano <gitster@pobox.com> writes: > > > Is this the answer to my question?
Sorry I forgot to add a reference to the thread from which the patch originated: http://groups.google.com/group/msysgit/msg/5da53cf1ccf417cf
> IOW, please try this patch. I am planning to queue it to 'maint' as part > of 1.7.0.1 if this is the right solution (which I obviously think it is).
Yes your patch does it correctly I just verified that the segfaults are gone as well. I think your solution is even nicer than mine. Thanks.
> -- >8 -- > From: Junio C Hamano <gitster@pobox.com> > Date: Mon, 15 Feb 2010 18:34:28 -0800 > Subject: [PATCH] Fix use of mutex in threaded grep
[...]
Show 12 quoted lines
> diff --git a/builtin-grep.c b/builtin-grep.c
> index 26d4deb..5c1545e 100644
> --- a/builtin-grep.c
> +++ b/builtin-grep.c
> @@ -81,8 +81,8 @@ static pthread_mutex_t read_sha1_mutex;
>
> #define grep_lock() pthread_mutex_lock(&grep_mutex)
> #define grep_unlock() pthread_mutex_unlock(&grep_mutex)
> -#define read_sha1_lock() pthread_mutex_lock(&read_sha1_mutex)
> -#define read_sha1_unlock() pthread_mutex_unlock(&read_sha1_mutex)
> +#define read_sha1_lock() do { if (use_threads) pthread_mutex_lock(&read_sha1_mutex); } while (0)
> +#define read_sha1_unlock() do { if (use_threads) pthread_mutex_unlock(&read_sha1_mutex); } while (0)One minor thing: Would it not be even nicer having the while loop inside the if clause? E.g like this
#define read_sha1_lock() if (use_threads) do { pthread_mutex_lock(&read_sha1_mutex); } while (0) #define read_sha1_unlock() if (use_threads) do { pthread_mutex_unlock(&read_sha1_mutex); } while (0)
If the purpose was to force a thread switch it is not necessary when not using threads.
cheers Heiko