Re: [PATCH 3/5] autoconf: Preliminary check for working mmap

From: Shawn Pearce <spearce@spearce.org>
Date: Sep 7, 2006, 05:58 UTC
Message-ID: <20060907055803.GE31580@spearce.org>
In-Reply-To: <7vodtt8l6v.fsf@assigned-by-dhcp.cox.net>

Junio C Hamano <junkio@cox.net> wrote:

Show 5 quoted lines

> Well, if you are talking about git.git t/ directory, I bet that
> "the full test suite" easily fits in a single window so much of
> the new code is not exercised, unless you have a runtime option
> to make use of very tiny window (32kB would be nice) for testing
> ;-).

Heh. t/ passed which meant basic rev listing and verify-pack appeared OK. I hardcoded the window size to be 2*getpagesize() (8192 bytes on my Mac OS X system) and started beating up Git against its own 8 MiB pack. The window code opened a ton of windows at once as the PACK_MAX_SZ was 128 MiB. So I hardcoded that to be 16384 bytes. And the code worked right against the 8 MiB Git pack by opening only 4 windows at once and closing the least-recently-used one.

I can easily parameterize both values in .git/config; there's no real reason for them to be hardcoded. That should make it easier to craft some new test cases that push the windowing code.

Show 11 quoted lines

> > I am going to rebase the changes to the 64 bit index in `pu`
> > and clean up my history.  Its currently one massive commit with
> > lots of changes that should be broken down into slightly more
> > digestable chunks.
> 
> Breaking things up would be nice.  Do you have a good testcase
> out of Mozilla repository that _needs_ 64-bit index?  The code
> in "pu" uses 64-bit index only 32-bit offset cannot describe the
> pack, so I only tested with an artificial case with the kernel
> archive with .idx converted with convert-idx to 64-bit.
>

Not really. We know the Mozilla pack decompressed is around 20 GiB. I could decompress it and repack it using no deltas; that should exceed 4 GiB. It will take quite some time to run the decompression and delta inflates, especially with the highly-compressed 450 MiB pack Jon Smirl sent me. I can do that kind of testing maybe later next week after I get my new amd64 system built.

-- 
Shawn.