tree 1f9c768a90c67c3c3b5ecaf09f426e7d0fbe1dda
parent bac5bd0ba6f2fc56c7850dff8da7454f800e0fe9
author Jesse McKenna <jessemckenna@google.com> 1565910724 -0700
committer Commit Bot <commit-bot@chromium.org> 1565911600 +0000

Teach gn to handle systems with > 64 processors

Previously, when run on Windows systems with > 64 logical processors,
gn's calculation of the number of available processors (used to
determine how many worker threads to create) under-counted the number of
processors, thereby not making full use of the system's available
processing power.

This change corrects gn's count of available CPUs so that it can use all
of the system's processors. In addition to creating the correct number
of workers, this change also distributes created workers between
processor groups, a necessary step when utilizing more than 64
processors on Windows.

On the 72-logical-processor P920, this change makes gn gen use all 36
cores, rather than only 18.

Bug: crbug.com/982982
Change-Id: I40b40f4d34b634566991e4bebf686f48836445e8
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/5660
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>