From: Nicolas Pitre <nico@cam.org>
Date: Sun, 18 Mar 2007 01:38:16 GMT
Subject: Re: [PATCH 2/2] Implement a simple delta_base cache
Message-ID: <alpine.LFD.0.83.0703172136440.18328@xanadu.home>
In-Reply-To: <Pine.LNX.4.64.0703171822280.4964@woody.linux-foundation.org>

On Sat, 17 Mar 2007, Linus Torvalds wrote:

> 
> 
> On Sat, 17 Mar 2007, Morten Welinder wrote:
> >
> > >         samples  %        app name                 symbol name
> > >         41527    15.6550  git                      strlen
> > 
> > Almost 16% in strlen?  Ugh!
> > 
> > That's a lot of strings, or perhaps very long strings.  Or a profiling bug.
> 
> It's likely real, and the problem is likely lots of small strings.
> 
> Each git tree entry is:
> 
> 	"<octal mode> name\0" <20-byte sha1>
> 
> so you do have a *lot* of strlen() calls when doing any tree parsing.

This is definitely an area where pack v4 will bring that cost down to 
zero.


Nicolas