From: Andreas Ericsson <ae@op5.se>
Date: Tue, 25 Sep 2007 19:10:06 GMT
Subject: Re: diffcore-rename performance mode
Message-ID: <46F95D0E.5090000@op5.se>
In-Reply-To: <20070925190640.GA4613@coredump.intra.peff.net>

Jeff King wrote:
> On Tue, Sep 25, 2007 at 12:38:43PM -0400, Jeff King wrote:
> 
>> [...]
>>
>> What is most confusing is why the 'somefree' case performs so badly,
>> since we should just be using the cnt_data. I'll see if gprof can shed
> 
> OK, I found the problem. estimate_similarity calls
> diff_populate_filespec each time, even if we already have the cnt_data,
> which leads to recomputing the blob contents from deltas. Oops.
> 
> Fixing this, the correct numbers are:
> 
>                  | stock | nofree | old somefree | fixed somefree
> -----------------|-----------------------------------------------
> user time (s)    | 76.78 | 16.96  | 46.26        | 16.99
> peak memory (Kb) | 52300 | 66796  | 59156        | 57328
> 
> So now we're at a 4.5x speedup for about 10% extra memory usage. Patch
> will follow.
> 

Nice work :)

-- 
Andreas Ericsson                   andreas.ericsson@op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231