cmd/guru: parallelize loop in globalReferrersPkgLevel

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)


Fixes golang/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>
2 files changed
tree: 2f70978d0a710c7c2a01603538bab7756bff367c
  1. benchmark/
  2. blog/
  3. cmd/
  4. container/
  5. cover/
  6. go/
  7. godoc/
  8. imports/
  9. internal/
  10. playground/
  11. present/
  12. refactor/
  13. third_party/
  14. .gitattributes
  15. .gitignore
  16. AUTHORS
  17. codereview.cfg
  18. CONTRIBUTING.md
  19. CONTRIBUTORS
  20. LICENSE
  21. PATENTS
  22. README.md
README.md

Go Tools

This subrepository holds the source for various packages and tools that support the Go programming language.

Some of the tools, godoc and vet for example, are included in binary Go distributions.

Others, including the Go guru and the test coverage tool, can be fetched with go get.

Packages include a type-checker for Go and an implementation of the Static Single Assignment form (SSA) representation for Go programs.

Download/Install

The easiest way to install is to run go get -u golang.org/x/tools/.... You can also manually git clone the repository to $GOPATH/src/golang.org/x/tools.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the tools repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/tools/(your subdir):” in the subject line, so it is easy to find.