Re: [PATCH] RFC: git lazy clone proof-of-concept

[Brandon Casey <casey@nrlssc.navy.mil>]

Nicolas Pitre wrote:
> On Sun, 10 Feb 2008, Johannes Schindelin wrote:
> 
>> I tried that:
>>
>> $ git config pack.deltaCacheLimit 1
>> $ git config pack.deltaCacheSize 1
>> $ git config pack.windowMemory 2g
> 
> This has nothing to do with repacking memory usage, but even tighter 
> packs can be obtained with:
> 
> 	git config repack.usedeltabaseoffset true
> 
> This is not the default yet.

I have successfully repacked this repo a few times on a 2.1GHz system with 16G.

The smallest attained pack was about 1.45G (1556569742B).

This run took about 7 hours 26 min.

I ran: git repack -a -d -f --window=250 --depth=250

Here are the relevent config entries:
[pack]
        threads = 1
        compression = 9
[repack]
        usedeltabaseoffset = true


Other runs:


* Same as above, but with default compression:

	pack size: 1560624388
	time: 7 hours 11 min

	Not much difference in time or size.


* Multi threaded (250m window)
[pack]
        threads = 4
        windowmemory = 250m
        compression = 9
[repack]
        usedeltabaseoffset = true

	pack size: 1767405703
	time: 3 hours

	First >99% took 50min. Last 10000 objects took 2hours.

* Multi threaded (500m window)
[pack]
        threads = 4
        windowmemory = 500m
        compression = 9
[repack]
        usedeltabaseoffset = true

	pack size: 1640820903
	time: forgot to time, but between 3-4 hours based on file time

	I just received Dscho's email, this is interesting to compare
	with his single threaded result of 1638490531. I wonder if he
	used deltabaseoffset? I think his machine is a little faster
	than this one. So using 4 threads finished twice as fast and
	produced a similar pack size. Actually, the difference could
	just be the compression setting.

* Deeper (git repack -a -d -f --window=250 --depth=500)
[pack]
        threads = 1
        compression = 9
[repack]
        usedeltabaseoffset = true

	pack size: 1578263745
	time: 7 hours 58 min

	Larger pack compared to --depth=250.

-brandon