Macro fusion merges two instructions to a single micro-op. Intel
core platform performs this hardware optimization under limited
circumstances. For example, CMP + JCC can be "fused" and executed
/retired together. While with sampling this can result in the
sample sometimes being on the JCC and sometimes on the CMP.
So for the fused instruction pair, they could be considered
together.
On Nehalem, fused instruction pairs:
cmp/test + jcc.
On other new CPU:
cmp/test/add/sub/and/inc/dec + jcc.
This patch series marks the case clearly by joining the fused
instruction pair in the arrow of the jump.
For example:
│ ┌──cmpl $0x0,argp_program_version_hook
81.93 │ ├──je 20
│ │ lock cmpxchg %esi,0x38a9a4(%rip)
│ │↓ jne 29
│ │↓ jmp 43
11.47 │20:└─→cmpxch %esi,0x38a999(%rip)
Change-log:
-----------
v3: 1. Add checking for Nehalem (CMP, TEST). For other newer
Intel CPUs just check it by default (CMP, TEST, ADD,
SUB, AND, INC, DEC).
2. Use Arnaldo's fix to let the display be better
v2: According to Arnaldo's comments, remove the weak function and
use an arch-specific function instead to check fused instruction
pair.
v1: Inital post
Jin Yao (2):
perf util: Check for fused instruction
perf report: Implement visual marker for macro fusion in annotate
tools/perf/arch/x86/annotate/instructions.c | 37 +++++++++++++++++++++++++++++
tools/perf/ui/browser.c | 29 ++++++++++++++++++++++
tools/perf/ui/browser.h | 2 ++
tools/perf/ui/browsers/annotate.c | 32 +++++++++++++++++++++++++
tools/perf/util/annotate.c | 17 +++++++++++++
tools/perf/util/annotate.h | 3 +++
6 files changed, 120 insertions(+)
--
2.7.4
