From: Nicolas Pitre <nico@cam.org>
Date: Thu, 06 Sep 2007 06:23:38 GMT
Subject: Re: [PATCH] basic threaded delta search
Message-ID: <alpine.LFD.0.9999.0709060220520.21186@xanadu.home>
In-Reply-To: <85ps0wfh8h.fsf@lola.goethe.zz>

On Thu, 6 Sep 2007, David Kastrup wrote:

> Nicolas Pitre <nico@cam.org> writes:
> 
> > this is still rough, hence it is disabled by default.  You need to compile
> > with "make THREADED_DELTA_SEARCH=1 ..." at the moment.
> >
> > Threading is done on different portions of the object list to be
> > deltified. This is currently done by spliting the list into n parts and
> > then a thread is spawned for each of them.  A better method would consist
> > of spliting the list into more smaller parts and have the n threads
> > pick the next part available.
> 
> In my experience, the worst performance hit happens when the real
> memory is exhausted and things start paging.  Threading on different
> portions of the object list is going to exacerbate the problem in the
> areas where it hits worst.

Just don't use it if you don't have 1) a SMP machine and 2) enough ram.
Threading will be enabled with a command line argument at some point.


Nicolas