This change parallelizes the outer loop in globalReferrersPkgLevel,
which loops over packages to inspect.
There is also an easily parallelizable inner loop.
However, parallelizing it adds complication
(deffiles needs a mutex, inQueryPackage requires a wait group)
and offers only a 2% speed-up.
Benchmarks for this change, looking for encoding/json.MarshalIndent:
name old time/op new time/op delta
Referrers 5.31s ± 2% 4.67s ± 3% -11.95% (p=0.000 n=10+10)
name old user-time/op new user-time/op delta
Referrers 15.9s ± 2% 16.5s ± 3% +3.71% (p=0.000 n=10+10)
name old sys-time/op new sys-time/op delta
Referrers 15.7s ± 3% 16.1s ± 3% +2.73% (p=0.011 n=10+10)
Fixesgolang/go#24272
Updates golang/go#25017
This work supported by Sourcegraph.
Change-Id: I5dcda9017103cdff59d0ffdf5e87d2c2c955a33a
Reviewed-on: https://go-review.googlesource.com/108878
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
d4c6246f3e