Re: [PATCH] revision.c: reduce object database queries

On 2/24/2018 8:34 PM, Derrick Stolee wrote:

In mark_parents_uninteresting(), we check for the existence of an
object file to see if we should treat a commit as parsed. The result
is to set the "parsed" bit on the commit.

Modify the condition to only check has_object_file() if the result
would change the parsed bit.

When a local branch is different from its upstream ref, "git status"
will compute ahead/behind counts. This uses paint_down_to_common()
and hits mark_parents_uninteresting(). On a copy of the Linux repo
with a local instance of "master" behind the remote branch
"origin/master" by ~60,000 commits, we find the performance of
"git status" went from 1.42 seconds to 1.32 seconds, for a relative
difference of -7.0%.

I do want to add that the exact same "git status" performance test with the commit-graph feature goes from 0.29 seconds to 0.21 seconds for a relative change of -27.5%.

Thanks,

-Stolee