[darcs-devel] darcs patch: (Re)upgrade createPS and generatePS to D... (and 8 more)

Don Stewart dons at galois.com
Wed Feb 6 16:46:44 UTC 2008


droundy:
> On Wed, Feb 06, 2008 at 04:42:02PM +0000, Eric Kow wrote:
> > So, I haven't had a chance to look into the freezing function yet, but
> > I did do an informal performance comparison using the Data.ByteString
> > version and the --disable-bytestring version.
> > 
> > In short, the bytestring upgrade helps... a little bit.
> > 
> > Doing a local get of the GHC repository, best of three trials, takes 2
> > minutes and 15 seconds (--disable-bytestring) and 1 minute 57 seconds
> > (Data.ByteString).  This is a 13% improvement in my calculations
> > (18/135s), which is not bad considering how little it cost us to
> > implement.
> 
> Sounds great!
> 
> Also worth testing is
> 
> time darcs pull -a && time darcs obliterate --last 100 -a
> 
> which you should repeat a few times (particularly as the first pull is
> likely to have no effect).  Also you can try this with --last 1000 to get a
> more vigorous test.
> 
> > Maybe we can egg on the bytestring people and get them to submit
> > patches taking this further down (for example, they could improve our
> > between newlines and nth newline stuff).
> 
> That'd be nice.

If you can get darcs working with bytestrings, I'm happy to write
bytestring-optimised variants of things you need, to squeeze out more 
performance.

-- Don


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