1063754 - Factory::HasSSE2 should cache its result

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Currently Factory::HasSSE2 on x86-32 does a couple of CPUID instructions. It gets called a lot, e.g. for every blur operation and every software-filter primitive evaluation. CPUID is slow so it's a good idea to cache the result of HasSSE2. Most other users of SSE2 do this.

Also, frequent use of CPUID triggers a hardware/hypervisor bug when running Firefox under rr in a virtual machine, so fixing this bug makes record and replay of Firefox in a VM more reliable.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5e6dbec98ec4

Comment 3

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5e6dbec98ec4