On Sat, 12 Jan 2008, Sam Vilain wrote:

quoted text
> Nicolas Pitre wrote:
> > Sorry to rain on your parade, but to me 6-10% time saving is not a clear 
> > win at all, given the equal increase in repository size.  This is simply 
> > not worth it.
> 
> Agree.
> 
> > And a 50% time saving on an operation, such a git log, which takes less 
> > than 2 seconds in absolute time, is not worth the repo size increase 
> > either.
> 
> Disagree.  Going as much as twice as fast for many history operations
> for 10% added space sounds like a clear win to me.

If you can come with a real life scenario, and not simply a simple test 
having little relevance with typical usage, that shows a clear reduction 
in execution time which is human perceptible, then I'll agree with you.  
But doing a full history log taking one second instead of two isn't a 
good enough argument  to me for making the repository many megabytes 
larger.  Again if it was 'git blame' using 5 seconds instead of 10 then 
I would agree that this is a clear win, even if this is also a 50% 
execution time reduction.  But human perception is way more important 
when it is 10 secs down to 5 compared to 2 secs down to 1.

This proposed change isn't free, because you have to introduce a 
regression in one place in order to make a gain somewhere else. The pack 
v4 format that I developed with Shawn, though, was showing _both_ a 
speed gain and a repository size reduction, hence there is no regression 
for the added improvements.  *That* is a clear win.

quoted text
> We can easily agree
> to disagree though

I suppose we do.


Nicolas
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