On Mon, Mar 18, 2019 at 01:28:24PM -0700, Jonathan Nieder wrote:

quoted

+Using this option may optimize for disk space at the expense of
+runtime performance. See the `--depth` and `--window` documentation in
+linkgit:git-repack[1]. It is not recommended that this option be used
+to improve performance for a given repository without running tailored
+performance benchmarks on it. It may make things better, or worse. Not
+using this at all is the right trade-off for most users and their
+repositories.

This part kind of feels like giving up.  Can we make --aggressive have
good runtime read performance so we don't have to hedge this way?
E.g. is this patch papering over a poor choice of --depth setting in
--aggressive?

I thought we already did that, in 07e7dbf0db (gc: default aggressive
depth to 50, 2016-08-11). As far as I know, "--aggressive" produces
packs with similar runtime performance.

It is possible, if it finds more deltas due to the larger window, that
we'd spend more time accessing those deltas. But if the chains aren't
long, the base cache tends to perform well, and delta reconstruction is
about the same cost as zlib inflating. And we have a smaller disk cache
footprint.

-Peff