Open Bug 1516809 Opened 6 years ago Updated 2 years ago

PGO should be disabled for performance critical parts that can not be trained

Categories

(Firefox Build System :: General, defect)

Product:
Firefox Build System
Component:
General
Version:
66 Branch
Type:
defect

Tracking

(Not tracked)

Status:
UNCONFIRMED

People

(Reporter: jh, Unassigned)

Details

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0 Steps to reproduce: Skia and other gfx libraries contains vector code that is build with PGO. Problem is that this instruct compiler to optimize agressively only those routines that was used on the specific ISA of the build machine. To get better peroformance across different CPUs these parts should be compiled with no profile feedback (either by setting right flags in Makefile or via no_instrument_function attribute supported by GCC and Clang)
Component: Untriaged → General
Product: Firefox → Firefox Build System
Severity: normal → S3
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