perf_event: Add alignment-faults and emulation-faults software events

Add two more software events that are common to many cpus.

Alignment faults: When a load or store is not aligned properly.

Emulation faults: When an instruction is emulated in software.

Both cause a very significant slowdown (100x or worse), so identifying and
fixing them is very important.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

include/linux/perf_counter.h

@@ -106,6 +106,8 @@ enum perf_sw_ids {
 	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 */
 };

include/linux/perf_event.h

@@ -102,6 +102,8 @@ enum perf_sw_ids {
 	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 */
 };

kernel/perf_event.c

@@ -4186,6 +4186,8 @@ static const struct pmu *sw_perf_event_init(struct perf_event *event)
 	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 (!event->parent) {
 			atomic_inc(&perf_swevent_enabled[event_id]);
 			event->destroy = sw_perf_event_destroy;

tools/perf/design.txt

@@ -137,6 +137,8 @@ enum sw_event_ids {
 	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

tools/perf/util/parse-events.c

@@ -46,6 +46,8 @@ static struct event_symbol event_symbols[] = {
   { 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_EVENT_FIELD(config, name) \
@@ -74,6 +76,8 @@ static const char *sw_event_names[] = {
 	"CPU-migrations",
 	"minor-faults",
 	"major-faults",
+	"alignment-faults",
+	"emulation-faults",
 };
 
 #define MAX_ALIASES 8