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authorAndi Kleen <ak@linux.intel.com>2016-05-30 18:49:42 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-06-06 23:04:15 +0300
commit44b1e60ab576c343aa592a2a6c679297cc69740d (patch)
treeaf5a5f995cb7e0f6ce9a57f9163386d9be1321ed /tools/perf/builtin-stat.c
parent17a2634bcb88e52bd637fdaa47d7ff0bddb0188f (diff)
downloadlinux-44b1e60ab576c343aa592a2a6c679297cc69740d.tar.xz
perf stat: Basic support for TopDown in perf stat
Add basic plumbing for TopDown in perf stat TopDown is intended to replace the frontend cycles idle/ backend cycles idle metrics in standard perf stat output. These metrics are not reliable in many workloads, due to out of order effects. This implements a new --topdown mode in perf stat (similar to --transaction) that measures the pipe line bottlenecks using standardized formulas. The measurement can be all done with 5 counters (one fixed counter) The result are four metrics: FrontendBound, BackendBound, BadSpeculation, Retiring that describe the CPU pipeline behavior on a high level. The full top down methology has many hierarchical metrics. This implementation only supports level 1 which can be collected without multiplexing. A full implementation of top down on top of perf is available in pmu-tools toplev. (http://github.com/andikleen/pmu-tools) The current version works on Intel Core CPUs starting with Sandy Bridge, and Atom CPUs starting with Silvermont. In principle the generic metrics should be also implementable on other out of order CPUs. TopDown level 1 uses a set of abstracted metrics which are generic to out of order CPU cores (although some CPUs may not implement all of them): topdown-total-slots Available slots in the pipeline topdown-slots-issued Slots issued into the pipeline topdown-slots-retired Slots successfully retired topdown-fetch-bubbles Pipeline gaps in the frontend topdown-recovery-bubbles Pipeline gaps during recovery from misspeculation These metrics then allow to compute four useful metrics: FrontendBound, BackendBound, Retiring, BadSpeculation. Add a new --topdown options to enable events. When --topdown is specified set up events for all topdown events supported by the kernel. Add topdown-* as a special case to the event parser, as is needed for all events containing -. The actual code to compute the metrics is in follow-on patches. v2: Use standard sysctl read function. v3: Move x86 specific code to arch/ v4: Enable --metric-only implicitly for topdown. v5: Add --single-thread option to not force per core mode v6: Fix output order of topdown metrics v7: Allow combining with -d v8: Remove --single-thread again v9: Rename functions, adding arch_ and topdown_. v10: Expand man page and describe TopDown better Paste intro into commit description. Print error when malloc fails. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: http://lkml.kernel.org/r/1464119559-17203-1-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-stat.c')
-rw-r--r--tools/perf/builtin-stat.c119
1 files changed, 116 insertions, 3 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ee7ada78d86f..fd76bb0b18d1 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -59,10 +59,13 @@
#include "util/thread.h"
#include "util/thread_map.h"
#include "util/counts.h"
+#include "util/group.h"
#include "util/session.h"
#include "util/tool.h"
+#include "util/group.h"
#include "asm/bug.h"
+#include <api/fs/fs.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <locale.h>
@@ -98,6 +101,15 @@ static const char * transaction_limited_attrs = {
"}"
};
+static const char * topdown_attrs[] = {
+ "topdown-total-slots",
+ "topdown-slots-retired",
+ "topdown-recovery-bubbles",
+ "topdown-fetch-bubbles",
+ "topdown-slots-issued",
+ NULL,
+};
+
static struct perf_evlist *evsel_list;
static struct target target = {
@@ -112,6 +124,7 @@ static volatile pid_t child_pid = -1;
static bool null_run = false;
static int detailed_run = 0;
static bool transaction_run;
+static bool topdown_run = false;
static bool big_num = true;
static int big_num_opt = -1;
static const char *csv_sep = NULL;
@@ -124,6 +137,7 @@ static unsigned int initial_delay = 0;
static unsigned int unit_width = 4; /* strlen("unit") */
static bool forever = false;
static bool metric_only = false;
+static bool force_metric_only = false;
static struct timespec ref_time;
static struct cpu_map *aggr_map;
static aggr_get_id_t aggr_get_id;
@@ -1520,6 +1534,14 @@ static int stat__set_big_num(const struct option *opt __maybe_unused,
return 0;
}
+static int enable_metric_only(const struct option *opt __maybe_unused,
+ const char *s __maybe_unused, int unset)
+{
+ force_metric_only = true;
+ metric_only = !unset;
+ return 0;
+}
+
static const struct option stat_options[] = {
OPT_BOOLEAN('T', "transaction", &transaction_run,
"hardware transaction statistics"),
@@ -1578,8 +1600,10 @@ static const struct option stat_options[] = {
"aggregate counts per thread", AGGR_THREAD),
OPT_UINTEGER('D', "delay", &initial_delay,
"ms to wait before starting measurement after program start"),
- OPT_BOOLEAN(0, "metric-only", &metric_only,
- "Only print computed metrics. No raw values"),
+ OPT_CALLBACK_NOOPT(0, "metric-only", &metric_only, NULL,
+ "Only print computed metrics. No raw values", enable_metric_only),
+ OPT_BOOLEAN(0, "topdown", &topdown_run,
+ "measure topdown level 1 statistics"),
OPT_END()
};
@@ -1772,12 +1796,62 @@ static int perf_stat_init_aggr_mode_file(struct perf_stat *st)
return 0;
}
+static int topdown_filter_events(const char **attr, char **str, bool use_group)
+{
+ int off = 0;
+ int i;
+ int len = 0;
+ char *s;
+
+ for (i = 0; attr[i]; i++) {
+ if (pmu_have_event("cpu", attr[i])) {
+ len += strlen(attr[i]) + 1;
+ attr[i - off] = attr[i];
+ } else
+ off++;
+ }
+ attr[i - off] = NULL;
+
+ *str = malloc(len + 1 + 2);
+ if (!*str)
+ return -1;
+ s = *str;
+ if (i - off == 0) {
+ *s = 0;
+ return 0;
+ }
+ if (use_group)
+ *s++ = '{';
+ for (i = 0; attr[i]; i++) {
+ strcpy(s, attr[i]);
+ s += strlen(s);
+ *s++ = ',';
+ }
+ if (use_group) {
+ s[-1] = '}';
+ *s = 0;
+ } else
+ s[-1] = 0;
+ return 0;
+}
+
+__weak bool arch_topdown_check_group(bool *warn)
+{
+ *warn = false;
+ return false;
+}
+
+__weak void arch_topdown_group_warn(void)
+{
+}
+
/*
* Add default attributes, if there were no attributes specified or
* if -d/--detailed, -d -d or -d -d -d is used:
*/
static int add_default_attributes(void)
{
+ int err;
struct perf_event_attr default_attrs0[] = {
{ .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK },
@@ -1896,7 +1970,6 @@ static int add_default_attributes(void)
return 0;
if (transaction_run) {
- int err;
if (pmu_have_event("cpu", "cycles-ct") &&
pmu_have_event("cpu", "el-start"))
err = parse_events(evsel_list, transaction_attrs, NULL);
@@ -1909,6 +1982,46 @@ static int add_default_attributes(void)
return 0;
}
+ if (topdown_run) {
+ char *str = NULL;
+ bool warn = false;
+
+ if (stat_config.aggr_mode != AGGR_GLOBAL &&
+ stat_config.aggr_mode != AGGR_CORE) {
+ pr_err("top down event configuration requires --per-core mode\n");
+ return -1;
+ }
+ stat_config.aggr_mode = AGGR_CORE;
+ if (nr_cgroups || !target__has_cpu(&target)) {
+ pr_err("top down event configuration requires system-wide mode (-a)\n");
+ return -1;
+ }
+
+ if (!force_metric_only)
+ metric_only = true;
+ if (topdown_filter_events(topdown_attrs, &str,
+ arch_topdown_check_group(&warn)) < 0) {
+ pr_err("Out of memory\n");
+ return -1;
+ }
+ if (topdown_attrs[0] && str) {
+ if (warn)
+ arch_topdown_group_warn();
+ err = parse_events(evsel_list, str, NULL);
+ if (err) {
+ fprintf(stderr,
+ "Cannot set up top down events %s: %d\n",
+ str, err);
+ free(str);
+ return -1;
+ }
+ } else {
+ fprintf(stderr, "System does not support topdown\n");
+ return -1;
+ }
+ free(str);
+ }
+
if (!evsel_list->nr_entries) {
if (target__has_cpu(&target))
default_attrs0[0].config = PERF_COUNT_SW_CPU_CLOCK;