[PATCH 4 of 4] revlog: add an aggressivemergedelta option

[Matt Mackall]

On Sun, 2015-08-30 at 15:09 -0700, Durham Goode wrote:
> # HG changeset patch
> # User Durham Goode <durham at fb.com>
> # Date 1440968612 25200
> #      Sun Aug 30 14:03:32 2015 -0700
> # Node ID ffaccbf9565ec5f73ded2ae3f9f611c943baad17
> # Parent  03338124de4c33848974b5a512d4e6ef71b4424b
> revlog: add an aggressivemergedelta option
> 
> This adds an option for delta'ing against both p1 and p2 when applying merge
> revisions and picking whichever is smallest.

I've queued all four of these, thanks.

> Some before and after stats on manifest.d size:
> 
> internal large repo:
> before: 1.2 GB
> after: 930 MB
> 
> mozilla-central:
> before: 261 MB
> after: 92 MB

This is big enough that I'd probably consider just enabling it all the
time. Two considerations here:

- bandwidth is typically scarcer than CPU
- it's a one-time cost at commit, rather than an on-going cost

-- 
Mathematics is the supreme nostalgia of our time.