openSUSE
firefox-3.0 package

  1. Bug #213708
  2. Comment #55

Comment 55 for bug 213708

Revision history for this message
In , B-jacques (b-jacques) wrote :

Created an attachment (id=372234)
Use -fprofile-correction and enable PGO for jemalloc

I tried Mozilla's PGO build and at one point or another, GCC would bail out complaining about corrupted profiling files, much like the issue that led to patch #305385. It turns out that GCC's profiling support was written without taking threaded applications into account, leading to inconsistencies in profiling information, which would then cause GCC to error out when reading them later.

In GCC-4.4, a new compiler flag was added to solve this issue:

"When using -fprofile-generate with a multi-threaded program, the profile counts may be slightly wrong due to race conditions. The new -fprofile-correction option directs the compiler to apply heuristics to smooth out the inconsistencies. By default the compiler will give an error message when it finds an inconsistent profile."

This patch adds a the -fprofile-correction flag to the PGO compiler flags and re-enables PGO for jemalloc. Naturally, this adds a dependency on GCC-4.4 for PGO.

(I was unable to reproduce bz's linking issue.)