[lttng-dev] [PATCH lttng-tools] Enable perf PMU counters by raw ID
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Tue Jun 21 20:20:22 UTC 2016
----- On Jun 21, 2016, at 3:18 PM, Julien Desfossez jdesfossez at efficios.com wrote:
> 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 <jdesfossez at efficios.com>
> ---
> 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(-)
>
> diff --git a/doc/man/lttng-add-context.1.txt b/doc/man/lttng-add-context.1.txt
> index f995a7f..4779672 100644
> --- a/doc/man/lttng-add-context.1.txt
> +++ b/doc/man/lttng-add-context.1.txt
> @@ -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.
>
> +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:
>
> diff --git a/include/lttng/event.h b/include/lttng/event.h
> index 16b4d4f..398f94c 100644
> --- a/include/lttng/event.h
> +++ b/include/lttng/event.h
> @@ -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 {
> diff --git a/src/bin/lttng-sessiond/context.c b/src/bin/lttng-sessiond/context.c
> index 9c3a394..81089b1 100644
> --- a/src/bin/lttng-sessiond/context.c
> +++ b/src/bin/lttng-sessiond/context.c
> @@ -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:
> diff --git a/src/bin/lttng-sessiond/trace-ust.c
> b/src/bin/lttng-sessiond/trace-ust.c
> index 1c325fb..b75d11b 100644
> --- a/src/bin/lttng-sessiond/trace-ust.c
> +++ b/src/bin/lttng-sessiond/trace-ust.c
> @@ -541,6 +541,7 @@ int trace_ust_context_type_event_to_ust(
> utype = LTTNG_UST_CONTEXT_IP;
> break;
> case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
> + case LTTNG_EVENT_CONTEXT_PERF_THREAD_RAW:
Do we really need to distinguish between
raw and non-raw counters in the sessiond ?
I thought the only difference would be when
parsing the command line/liblttng-ctl.
> if (!ustctl_has_perf_counters()) {
> utype = -1;
> WARN("Perf counters not implemented in UST");
> diff --git a/src/bin/lttng/commands/add_context.c
> b/src/bin/lttng/commands/add_context.c
> index 2f43dc7..4db9bd2 100644
> --- a/src/bin/lttng/commands/add_context.c
> +++ b/src/bin/lttng/commands/add_context.c
> @@ -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
> +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)
> {
> - 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 +797,14 @@ 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);
Missing NULL check.
Thanks,
Mathieu
> + goto found;
> + }
> +
> /*
> * No match found against static contexts; check if it is an app
> * context.
> --
> 1.9.1
>
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--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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