Re: Decompression speed: zip vs lzo

[Sam Vilain <sam@vilain.net>]

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.  We can easily agree
to disagree though - making it a disabled by default config option
allows the user to unroll their packs if they want.

> Going from 2 seconds down to one second doesn't make enough of 
> a user experience difference.

What do you mean?  1 second waiting is far better than 2 seconds
waiting.  And the mmap optimizations have not even begun yet - that
could result in boosts from zero-copy, such as a lighter VM footprint.

> If git blame was to go from 10 seconds down to 4 then I'd say this is a 
> clear win.  But this is not the case.

This is an awesome boost!  Everything feels snappier already :)

maia:~/src/perl.clean$ time git-log | LANG=C wc
 288927  894027 8860916

real    0m0.839s
user    0m0.824s
sys     0m0.144s
maia:~/src/perl.clean$ cd ../perl.clean.loose/
maia:~/src/perl.clean.loose$ time git-log | LANG=C wc
 288927  894027 8860916

real    0m0.515s
user    0m0.504s
sys     0m0.136s

maia:~/src/perl.clean.loose$ du -sk .git/objects/pack/
113484  .git/objects/pack/
maia:~/src/perl.clean.loose$ cd -
/home/samv/src/perl.clean
maia:~/src/perl.clean$ du -sk .git/objects/pack/
107040  .git/objects/pack/
maia:~/src/perl.clean$

Want me to try this on kde.git?

Sam.