1821671 - Enable using more than two threads for parallel marking

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P2)

Description

[Jon Coppeard (:jonco)]

To start with let's use the following formula for the number of threads to use:

Min(LogicalCores, 8) / 2

That's pretty much what we use elsewhere. We can then validate that this improves performance without using excessive resources and adjust as necessary.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1821671 - Part 1: Add a GC parameter to set the maximum number of marking threads r?sfink

Currently there's a parameter to set the number of marking threads used, but we
actually want is to calculate this internally based on the number of cores but
with some limit.

The patch adds a parameter for the maximum and makes the existing parameter for
the number of marking threads read-only. The shell options for setting marking
threads is removed (the new parameter can bet set with --gc-param).

This new parameter will be used in a performance experiment to measure the
effect of using more threads for parallel marking.

Comment 2

[Jon Coppeard (:jonco)]

Attachment: Bug 1821671 - Part 2: Add pref for setting the maximum number of marking threads to use r?sfink

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/2f0d4d6a6538
Part 1: Add a GC parameter to set the maximum number of marking threads r=sfink

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ba8edf289d8e
Part 2: Add pref for setting the maximum number of marking threads to use r=sfink

Comment 5

[Aron Cseh]

https://hg.mozilla.org/mozilla-central/rev/2f0d4d6a6538

Comment 6

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/ba8edf289d8e