Re: irc usage..

From: Martin Langhoff <martin.langhoff@gmail.com>
Date: Jun 5, 2006, 02:06 UTC
Message-ID: <46a038f90606041906k66d85152v6e402c65151d7ab8@mail.gmail.com>
In-Reply-To: <44837BDB.2090601@gentoo.org>

On 6/5/06, Alec Warner <antarus@gentoo.org> wrote:

Show 6 quoted lines

> Ok the box this was running on had issues, so I switched to using
> pearl.amd64.dev.gentoo.org, a dual core amd64 X2 4600+ with 4 gigs of
> ram and plenty of disk.  The "problem" now is just converstion time...30
> hours and I'm into 2004-09-17...but it's been in 2004 all day, seems
> like most of the commits are in the last three years.  Are there
> architectural issues with doing this in parallel?

I don't think you can do this in parallel. What I would do is remove the -a from the git-repack invocation. It does hurt import times quite a bit -- just do a git-repack -a -d when it's done.

And... having said that, there is still a memory leak somehow, somewhere. It's been evading me for 2 weeks now, so I feel an idiot now. Not too bad in general, but it shows clearly in the gentoo and mozilla imports.

> Since the repository commits are all in cvs, it should be possible to do
> the work in parallel, since you know what all the commits touch.  The
> concern would be ordering of nodes in the tree; you'd end up building a
> bunch of subtrees and patching them together?

Well... parsecvs does a bit of this but in sequential fashion... it imports all the files first, and then runs through the history building the tree+commits in order, committing them. It saves a lot of time in the file imports by parsing the RCS file directly. The downside is that it must keep a filename+version=>sha1 mapping -- which I think is why parsecvs won't fit in memory until it's changed to store it on disk somehow ;-)

You are forced to do it in a sequence because cvsps only tells you about the files added/removed/changed in a commit -- you need the ancestor to have a view of what the whole tree looked like. The only room for parallelism I see is to fork off new processes to work on branches in parallel.

martin