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 <jdesfos...@efficios.com>
---
doc/man/lttng-add-context.1.txt | 8 +++
src/bin/lttng/commands/add_context.c | 94 +++++++++++++++++++++++++++++++++++-
2 files changed, 101 insertions(+), 1 deletion(-)
diff --git a/doc/man/lttng-add-context.1.txt b/doc/man/lttng-add-context.1.txt
index f995a7f..c43581a 100644
--- a/doc/man/lttng-add-context.1.txt
+++ b/doc/man/lttng-add-context.1.txt
@@ -45,6 +45,14 @@ 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.
+It is also possible to enable PMU counters by raw ID using the
+`perf:cpu:raw:r<N>:<name>` or `perf:thread:raw:r<N>:<name>` format for the
+kernel and user-space respectively. `<N>` is a hexadecimal event descriptor
+which is the same format as perf-record(1): a concatenation of the `Umask
+value` and `Event number` provided by the processors manufacturer. 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:
diff --git a/src/bin/lttng/commands/add_context.c
b/src/bin/lttng/commands/add_context.c
index 2f43dc7..711c1e0 100644
--- a/src/bin/lttng/commands/add_context.c
+++ b/src/bin/lttng/commands/add_context.c
@@ -87,6 +87,7 @@ enum perf_type {
PERF_TYPE_HARDWARE = 0,
PERF_TYPE_SOFTWARE = 1,
PERF_TYPE_HW_CACHE = 3,
+ PERF_TYPE_RAW = 4,
};
enum perf_count_hard {
@@ -688,9 +689,88 @@ end:
}
static
+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_COUNTER;
+ } else if (strncmp(next, "thread", 4) == 0) {
+ type->opt->ctx_type =
CONTEXT_PERF_THREAD_COUNTER;
+ } 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)
{
- 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;
@@ -713,6 +793,18 @@ struct ctx_type *get_context_type(const char *ctx)
goto found;
}
+ /* Check if ctx is a raw perf context. */
+ ret = find_ctx_type_perf_raw(ctx, type);
+ if (ret == 0) {
+ type->opt->u.perf.type = PERF_TYPE_RAW;
+ type->opt->symbol = strdup(ctx);
+ if (!type->opt->symbol) {
+ PERROR("Copy perf field name");
+ goto not_found;
+ }
+ goto found;
+ }
+
/*
* No match found against static contexts; check if it is an app
* context.
--
1.9.1
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