[PATCH] perf_counter: Add alignment-faults and emulation-faults swevents

From: Anton Blanchard
Date: Mon Jul 06 2009 - 08:09:05 EST



Add two software events that are common to many cpus:

Alignment faults: When a load or store is not aligned properly and must be
performed by the kernel.

Emulation faults: When an instruction must be emulated by the kernel.

Both cause a very significant slowdown (potentially 100x or worse), so
identifying and fixing them is very important.

Signed-off-by: Anton Blanchard <anton@xxxxxxxxx>
---

Index: linux.trees.git/include/linux/perf_counter.h
===================================================================
--- linux.trees.git.orig/include/linux/perf_counter.h 2009-07-06 21:50:53.000000000 +1000
+++ linux.trees.git/include/linux/perf_counter.h 2009-07-06 21:51:18.000000000 +1000
@@ -102,6 +102,8 @@
PERF_COUNT_SW_CPU_MIGRATIONS = 4,
PERF_COUNT_SW_PAGE_FAULTS_MIN = 5,
PERF_COUNT_SW_PAGE_FAULTS_MAJ = 6,
+ PERF_COUNT_SW_ALIGNMENT_FAULTS = 7,
+ PERF_COUNT_SW_EMULATION_FAULTS = 8,

PERF_COUNT_SW_MAX, /* non-ABI */
};
Index: linux.trees.git/kernel/perf_counter.c
===================================================================
--- linux.trees.git.orig/kernel/perf_counter.c 2009-07-06 21:50:53.000000000 +1000
+++ linux.trees.git/kernel/perf_counter.c 2009-07-06 21:51:18.000000000 +1000
@@ -3754,6 +3754,8 @@
case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
case PERF_COUNT_SW_CONTEXT_SWITCHES:
case PERF_COUNT_SW_CPU_MIGRATIONS:
+ case PERF_COUNT_SW_ALIGNMENT_FAULTS:
+ case PERF_COUNT_SW_EMULATION_FAULTS:
if (!counter->parent) {
atomic_inc(&perf_swcounter_enabled[event]);
counter->destroy = sw_perf_counter_destroy;
Index: linux.trees.git/tools/perf/design.txt
===================================================================
--- linux.trees.git.orig/tools/perf/design.txt 2009-07-06 21:50:53.000000000 +1000
+++ linux.trees.git/tools/perf/design.txt 2009-07-06 21:51:18.000000000 +1000
@@ -137,6 +137,8 @@
PERF_COUNT_SW_CPU_MIGRATIONS = 4,
PERF_COUNT_SW_PAGE_FAULTS_MIN = 5,
PERF_COUNT_SW_PAGE_FAULTS_MAJ = 6,
+ PERF_COUNT_SW_ALIGNMENT_FAULTS = 7,
+ PERF_COUNT_SW_EMULATION_FAULTS = 8,
};

Counters of the type PERF_TYPE_TRACEPOINT are available when the ftrace event
Index: linux.trees.git/tools/perf/util/parse-events.c
===================================================================
--- linux.trees.git.orig/tools/perf/util/parse-events.c 2009-07-06 21:51:12.000000000 +1000
+++ linux.trees.git/tools/perf/util/parse-events.c 2009-07-06 21:51:18.000000000 +1000
@@ -38,6 +38,8 @@
{ CSW(PAGE_FAULTS_MAJ), "major-faults", "" },
{ CSW(CONTEXT_SWITCHES), "context-switches", "cs" },
{ CSW(CPU_MIGRATIONS), "cpu-migrations", "migrations" },
+ { CSW(ALIGNMENT_FAULTS), "alignment-faults", "" },
+ { CSW(EMULATION_FAULTS), "emulation-faults", "" },
};

#define __PERF_COUNTER_FIELD(config, name) \
@@ -66,6 +68,8 @@
"CPU-migrations",
"minor-faults",
"major-faults",
+ "alignment-faults",
+ "emulation-faults",
};

#define MAX_ALIASES 8
--
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