Re: [PATCH] MSVC: Windows-native implementation for subset of Pthreads API

From: Nicolas Pitre <nico@fluxnic.net>
To: "Andrzej K. Haczewski" <ahaczewski@gmail.com>
Cc: git@vger.kernel.org, Johannes Sixt <j.sixt@viscovery.net>
Subject: Re: [PATCH] MSVC: Windows-native implementation for subset of Pthreads API
Date: Wed, 04 Nov 2009 19:22:01 -0500 (EST)	[thread overview]
Message-ID: <alpine.LFD.2.00.0911041915120.10340@xanadu.home> (raw)
In-Reply-To: <4AF214D5.6050202@gmail.com>

On Thu, 5 Nov 2009, Andrzej K. Haczewski wrote:

> @@ -1638,6 +1657,8 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
>  				delta_search_threads);
>  	p = xcalloc(delta_search_threads, sizeof(*p));
>  
> +	init_threaded_search();

Careful.  At the beginning of the function you'll find:

        if (delta_search_threads <= 1) {
                find_deltas(list, &list_size, window, depth, processed);
                return;
        }

That is, if we have thread support compiled in but we're told to use 
only one thread, then the bulk of the work splitting is bypassed 
entirely.  Inside find_deltas() there will still be pthread_mutex_lock() 
and pthread_mutex_unlock() calls even if no threads are spawned.

Nicolas