Enable perf PMU counters by raw ID

Allow enabling perf PMU counters by raw ID in addition to the generic list already provided. The format for kernel tracing is "perf:cpu:raw:rNNN:<name>" and "perf:thread:raw:rNNN:<name> for user-space. The rNNN format is the same as perf-record(1) where NNN is a hexadecimal event descriptor in the form of umask+eventsel. The <name> field allows the user to give a more friendly name.

Example usage on Intel i7-3520M to get the unhalted reference cycles (eventsel: 0x13c) count at privilege level 0 (umask: 0x00):
lttng add-context -k -t perf:cpu:raw:r0013c:x86unhalted

Result in the trace:

sched_switch: { cpu_id = 3 }, {
	perf_cpu_raw_r0013c_x86unhalted = 27632578 }, [...]

Signed-off-by Julien Desfossez <[email protected]>

---

doc/man/lttng-add-context.1.txt      |  7 +++
include/lttng/event.h                |  2 +
src/bin/lttng-sessiond/context.c     |  1 +
src/bin/lttng-sessiond/trace-ust.c   |  1 +
src/bin/lttng/commands/add_context.c | 94 +++++++++++++++++++++++++++++++++++-
5 files changed, 104 insertions(+), 1 deletion(-)

doc/man/lttng-add-context.1.txt +0 -0

index f995a7f..4779672 100644
@@ -45,6 +45,13 @@ per-thread (`perf:thread:` prefix) counters. Currently,

per-CPU counters
can only be used in the Linux kernel tracing domain, while per-thread counters can only be used in the user space tracing domain.

doc/man/lttng-add-context.1.txt +7 -0

+It is also possible to enable PMU counters by raw ID using the
+`perf:cpu:raw:rNNN:<name>` or `perf:thread:raw:rNNN:<name>` format for the
+kernel and user-space respectively. `NNN` is a hexadecimal event descriptor
+(umask+eventsel) just like with perf-record(1), the possible values for this
+field are processor-specific. The `<name>` field is used to give a symbolic
+name to the counter in the trace.
+

Application-specific context fields can be added to a channel using the following syntax:

include/lttng/event.h +2 -0

index 16b4d4f..398f94c 100644
@@ -142,6 +142,8 @@ enum lttng_event_context_type {
 	LTTNG_EVENT_CONTEXT_PREEMPTIBLE		= 17,
 	LTTNG_EVENT_CONTEXT_NEED_RESCHEDULE	= 18,
 	LTTNG_EVENT_CONTEXT_MIGRATABLE		= 19,
+	LTTNG_EVENT_CONTEXT_PERF_CPU_RAW	= 20,
+	LTTNG_EVENT_CONTEXT_PERF_THREAD_RAW	= 21,
 };
 
 enum lttng_event_field_type {

src/bin/lttng-sessiond/context.c +1 -0

index 9c3a394..81089b1 100644
@@ -227,6 +227,7 @@ int context_kernel_add(struct ltt_kernel_session *ksession,
 		break;
 	case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
 	case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
+	case LTTNG_EVENT_CONTEXT_PERF_CPU_RAW:
 		kctx->ctx.ctx = LTTNG_KERNEL_CONTEXT_PERF_CPU_COUNTER;
 		break;
 	case LTTNG_EVENT_CONTEXT_INTERRUPTIBLE:

src/bin/lttng-sessiond/trace-ust.c +0 -0

index 1c325fb..b75d11b 100644

src/bin/lttng-sessiond/trace-ust.c +0 -0

 		if (!ustctl_has_perf_counters()) {
 			utype = -1;
 			WARN("Perf counters not implemented in UST");

src/bin/lttng/commands/add_context.c +5 -0

index 2f43dc7..4db9bd2 100644
@@ -78,6 +78,8 @@ enum context_type {
 	CONTEXT_PREEMPTIBLE  = 17,
 	CONTEXT_NEED_RESCHEDULE = 18,
 	CONTEXT_MIGRATABLE   = 19,
+	CONTEXT_PERF_CPU_RAW = 20,
+	CONTEXT_PERF_THREAD_RAW = 21,
 };
 
 /*

@@ -87,6 +89,7 @@ enum perf_type {
 	PERF_TYPE_HARDWARE = 0,
 	PERF_TYPE_SOFTWARE = 1,
 	PERF_TYPE_HW_CACHE = 3,
+	PERF_TYPE_RAW = 4,
 };
 
 enum perf_count_hard {

@@ -564,6 +567,8 @@ static int add_context(char *session_name)
 		case LTTNG_EVENT_CONTEXT_PERF_COUNTER:
 		case LTTNG_EVENT_CONTEXT_PERF_CPU_COUNTER:
 		case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
+		case LTTNG_EVENT_CONTEXT_PERF_CPU_RAW:
+		case LTTNG_EVENT_CONTEXT_PERF_THREAD_RAW:
 			context.u.perf_counter.type = type->opt->u.perf.type;
 			context.u.perf_counter.config = type->opt->u.perf.config;
 			strncpy(context.u.perf_counter.name, type->opt->symbol,

@@ -688,9 +693,88 @@ end:
 }
 

static

src/bin/lttng/commands/add_context.c +79 -0

+int find_ctx_type_perf_raw(const char *ctx, struct ctx_type *type)
+{
+	char *next;
+	int ret;
+	int field_pos = 0;
+	char *tmp_list;
+
+	tmp_list = strdup(ctx);
+	if (!tmp_list) {
+		PERROR("strdup temp list");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	/* Looking for "perf:[cpu|thread]:raw:<mask>:<name>". */
+	for (;;) {
+		next = strtok(tmp_list, ":");
+		if (!next) {
+			break;
+		}
+		tmp_list = NULL;
+		switch (field_pos) {
+		case 0:
+			if (strncmp(next, "perf", 4) != 0) {
+				ret = -1;
+				goto end;
+			}
+			break;
+		case 1:
+			if (strncmp(next, "cpu", 3) == 0) {
+				type->opt->ctx_type = CONTEXT_PERF_CPU_RAW;
+			} else if (strncmp(next, "thread", 4) == 0) {
+				type->opt->ctx_type = CONTEXT_PERF_THREAD_RAW;
+			} else {
+				ret = -1;
+				goto end;
+			}
+			break;
+		case 2:
+			if (strncmp(next, "raw", 3) != 0) {
+				ret = -1;
+				goto end;
+			}
+			break;
+		case 3:
+			if (strlen(next) < 2 || next[0] != 'r') {
+				ERR("Wrong perf raw mask format: rNNN");
+				ret = -1;
+				goto end;
+			}
+			type->opt->u.perf.config = strtoll(next +  1, NULL, 16);
+			break;
+		case 4:
+			/* name */
+			break;
+		case 5:
+			ERR("Too many ':' in perf raw format");
+			ret = -1;
+			goto end;
+		};
+		field_pos++;
+	}
+
+	if (field_pos < 5) {
+		ERR("Wrong perf raw format");
+		ret = -1;
+		goto end;
+	}
+
+	ret = 0;
+	goto end;
+
+end:
+	free(tmp_list);
+error:
+	return ret;
+}
+
+static

struct ctx_type *get_context_type(const char *ctx) {

src/bin/lttng/commands/add_context.c +1 -1

-	int opt_index;
+	int opt_index, ret;

	struct ctx_type *type = NULL;
	const char app_ctx_prefix[] = "$app.";
	char *provider_name = NULL, *ctx_name = NULL;

src/bin/lttng/commands/add_context.c +3 -1

+		goto found;
+	}
+
 	/*
 	 * No match found against static contexts; check if it is an app
 	 * context.
--

1.9.1

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