| commit | ee02cb3660d9ee29bf6eb176c03d803a6e8ab657 | |
| author | Guilherme Ottoni <ottoni@fb.com> | |
| Mon, 18 May 2015 17:35:28 +0000 (18 10:35 -0700) | ||
| committer | hhvm-bot <hhvm-bot@fb.com> | |
| Mon, 18 May 2015 18:00:34 +0000 (18 11:00 -0700) | ||
| tree | e7b620586b49fdedc61af81047fe750ec9856a8c | treesnapshot (tar.gz zip) |
| parent | 21bec8823465677bb24d249a0bbd35f81ec89129 | commitdiff |
Add a profile-guided code layout pass
Summary: This diff implements a profile-guided code layout pass, and enables it
for all PGO-based, Optimize translations. The method implemented here
is described in "Profile Guided Code Positioning" (PLDI'1990) by
Pettis & Hansen (more specifically, Algo2, from section 4.2.1). This
implementation uses estimated arc weights derived from a combination
of profile counters inserted at the bytecode-level blocks (in Profile
translations) and the JIT-time Likely/Unlikely/Unused hints (encoded
in the "area" field of the Vblocks).
Reviewed By: @jdelong
Differential Revision: D2073974
Summary: This diff implements a profile-guided code layout pass, and enables it
for all PGO-based, Optimize translations. The method implemented here
is described in "Profile Guided Code Positioning" (PLDI'1990) by
Pettis & Hansen (more specifically, Algo2, from section 4.2.1). This
implementation uses estimated arc weights derived from a combination
of profile counters inserted at the bytecode-level blocks (in Profile
translations) and the JIT-time Likely/Unlikely/Unused hints (encoded
in the "area" field of the Vblocks).
Reviewed By: @jdelong
Differential Revision: D2073974