From: Yakov Lerner <iler.ml@gmail.com>
Date: Mon, 03 Jul 2006 14:54:01 GMT
Subject: Re: Compression speed for large files
Message-ID: <f36b08ee0607030754k4d10548pfb71dc62c6ee0b21@mail.gmail.com>
In-Reply-To: <Pine.LNX.4.64.0607031030150.1213@localhost.localdomain>

On 7/3/06, Nicolas Pitre <nico@cam.org> wrote:
> On Mon, 3 Jul 2006, Joachim Berdal Haga wrote:
>
> > Alex Riesen wrote:
> > > On 7/3/06, Joachim B Haga <cjhaga@fys.uio.no> wrote:
> > > > So: is it a good idea to change to faster compression, at least for larger
> > > > files? From my (limited) testing I would suggest using Z_BEST_COMPRESSION
> > > > only for small files (perhaps <1MB?) and
> > > > Z_DEFAULT_COMPRESSION/Z_BEST_SPEED for
> > > > larger ones.
> > >
> > > Probably yes, as a per-repo config option.
> >
> > I can send a patch later. If it's to be a per-repo option, it's probably too
> > confusing with several values. Is it ok with
> >
> > core.compression = [-1..9]
> >
> > where the numbers are the zlib/gzip constants,
> >   -1 = zlib default (currently 6)
> >    0 = no compression
> > 1..9 = various speed/size tradeoffs (9 is git default)

It would be arguable whether, say, 10% better compression is worth
x(3-8) slower compression. But 3-4% better compression at the cost of
x(3-8) slower compression time as data suggest ? I think this begs
for switching the default to Z_DEFAULT_COMPRESSION

Yakov