On 10/3/2018 2:51 PM, Jeff King wrote:

On Wed, Oct 03, 2018 at 08:47:11PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

On Wed, Oct 03 2018, Stefan Beller wrote:

quoted

quoted

So we wouldn't be spending 5 minutes repacking linux.git right after
cloning it, just ~10s generating the commit graph, and the same would
happen if you rm'd .git/objects/info/commit-graph and ran "git commit",
which would kick of "gc --auto" in the background and do the same thing.

Or generating local bitmaps or pack idx files as well?

I'm less familiar with this area, but when I clone I get a pack *.idx
file, why does it need to be regenerated?

But yeah, in principle this would be a sensible addition, but I'm not
aware of cases where clients get significant benefits from bitmaps (see
https://githubengineering.com/counting-objects/), and I don't turn it on
for clients, but maybe I've missed something.

They don't help yet, and there's no good reason to enable bitmaps for
clients. I have a few patches that use bitmaps for things like
ahead/behind and --contains checks, but the utility of those may be
lessened quite a bit by Stolee's commit-graph work.  And if it isn't,
I'm mildly in favor of replacing the existing .bitmap format with
something better integrated with commit-graphs (which would give us an
opportunity to clean up some of the rough edges).

If the commit-graph doesn't improve enough on those applications, then 
we could consider adding a commit-to-commit reachability bitmap inside 
the commit-graph. ;)

-Stolee