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Message-ID: <CAP-5=fVAPGqbQigSDvvgzPap2shLJ=QPT4GE9oeGv-N0Awz5cA@mail.gmail.com>
Date: Fri, 6 May 2022 01:25:55 -0700
From: Ian Rogers <irogers@...gle.com>
To: zhengjun.xing@...ux.intel.com
Cc: acme@...nel.org, peterz@...radead.org, mingo@...hat.com,
alexander.shishkin@...el.com, jolsa@...hat.com,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
adrian.hunter@...el.com, ak@...ux.intel.com,
kan.liang@...ux.intel.com
Subject: Re: [PATCH 1/3] perf stat: Support metrics with hybrid events
and should be beefor eit.
On Thu, Apr 21, 2022 at 11:56 PM <zhengjun.xing@...ux.intel.com> wrote:
>
> From: Zhengjun Xing <zhengjun.xing@...ux.intel.com>
>
> One metric such as 'Kernel_Utilization' may be from different PMUs and
> consists of different events.
>
> For core,
> Kernel_Utilization = cpu_clk_unhalted.thread:k / cpu_clk_unhalted.thread
>
> For atom,
> Kernel_Utilization = cpu_clk_unhalted.core:k / cpu_clk_unhalted.core
>
> The metric group string for core is:
> '{cpu_clk_unhalted.thread/metric-id=cpu_clk_unhalted.thread:k/k,cpu_clk_unhalted.thread/metric-id=cpu_clk_unhalted.thread/}:W'
> It's internally expanded to:
> '{cpu_clk_unhalted.thread_p/metric-id=cpu_clk_unhalted.thread_p:k/k,cpu_clk_unhalted.thread/metric-id=cpu_clk_unhalted.thread/}:W#cpu_core'
>
> The metric group string for atom is:
> '{cpu_clk_unhalted.core/metric-id=cpu_clk_unhalted.core:k/k,cpu_clk_unhalted.core/metric-id=cpu_clk_unhalted.core/}:W'
> It's internally expanded to:
> '{cpu_clk_unhalted.core/metric-id=cpu_clk_unhalted.core:k/k,cpu_clk_unhalted.core/metric-id=cpu_clk_unhalted.core/}:W#cpu_atom'
>
> That means the group "{cpu_clk_unhalted.thread:k,cpu_clk_unhalted.thread}:W"
> is from cpu_core PMU and the group "{cpu_clk_unhalted.core:k,cpu_clk_unhalted.core}"
> is from cpu_atom PMU. And then next, check if the events in the group are
> valid on that PMU. If one event is not valid on that PMU, the associated
> group would be removed internally.
>
> In this example, cpu_clk_unhalted.thread is valid on cpu_core and
> cpu_clk_unhalted.core is valid on cpu_atom. So the checks for these two
> groups are passed.
>
> Before:
>
> # ./perf stat -M Kernel_Utilization -a sleep 1
> WARNING: events in group from different hybrid PMUs!
> WARNING: grouped events cpus do not match, disabling group:
> anon group { CPU_CLK_UNHALTED.THREAD_P:k, CPU_CLK_UNHALTED.THREAD_P:k, CPU_CLK_UNHALTED.THREAD, CPU_CLK_UNHALTED.THREAD }
>
> Performance counter stats for 'system wide':
>
> 17,639,501 cpu_atom/CPU_CLK_UNHALTED.CORE/ # 1.00 Kernel_Utilization
> 17,578,757 cpu_atom/CPU_CLK_UNHALTED.CORE:k/
> 1,005,350,226 ns duration_time
> 43,012,352 cpu_core/CPU_CLK_UNHALTED.THREAD_P:k/ # 0.99 Kernel_Utilization
> 17,608,010 cpu_atom/CPU_CLK_UNHALTED.THREAD_P:k/
> 43,608,755 cpu_core/CPU_CLK_UNHALTED.THREAD/
> 17,630,838 cpu_atom/CPU_CLK_UNHALTED.THREAD/
> 1,005,350,226 ns duration_time
>
> 1.005350226 seconds time elapsed
>
> After:
>
> # ./perf stat -M Kernel_Utilization -a sleep 1
>
> Performance counter stats for 'system wide':
>
> 17,981,895 CPU_CLK_UNHALTED.CORE [cpu_atom] # 1.00 Kernel_Utilization
> 17,925,405 CPU_CLK_UNHALTED.CORE:k [cpu_atom]
> 1,004,811,366 ns duration_time
> 41,246,425 CPU_CLK_UNHALTED.THREAD_P:k [cpu_core] # 0.99 Kernel_Utilization
> 41,819,129 CPU_CLK_UNHALTED.THREAD [cpu_core]
> 1,004,811,366 ns duration_time
>
> 1.004811366 seconds time elapsed
>
> Signed-off-by: Zhengjun Xing <zhengjun.xing@...ux.intel.com>
> Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
Sorry for the late review, this arrived April 21st and was added to
acme/perf/core on April 22nd - I was on vacation those days. There is
substantial complexity added here and I'm confused by the all too
frequent is_hybrid paths. There is nothing wrong in my eyes with
making the metric code sensitive to a PMU type, why does hybrid need
to be special? More comments below.
> ---
> tools/perf/util/metricgroup.c | 263 ++++++++++++++++++++++++++++++---
> tools/perf/util/stat-display.c | 8 +-
> 2 files changed, 249 insertions(+), 22 deletions(-)
>
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index d8492e339521..126a43a8917e 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -141,6 +141,11 @@ struct metric {
> * output.
> */
> const char *metric_unit;
> + /**
> + * The name of the CPU such as "cpu_core" or "cpu_atom" in hybrid systems
> + * and "NULL" in non-hybrid systems.
> + */
> + const char *pmu_name;
Thanks for the comment. CPU and PMU don't align, but I think PMU is
the better name. I think this is an optional PMU name used for opening
the metric's events. For example, on hybrid it can be cpu_core or
cpu_atom. This is confusing when we have a metric that mixes say core
and uncore events.
> /** Optional null terminated array of referenced metrics. */
> struct metric_ref *metric_refs;
> /**
> @@ -215,6 +220,7 @@ static struct metric *metric__new(const struct pmu_event *pe,
> }
> m->metric_expr = pe->metric_expr;
> m->metric_unit = pe->unit;
> + m->pmu_name = pe->pmu;
Well this explains why we have a pmu_name. I'm not a fan of metrics
being the same as events. Reading the PMU here feels a bit of a hack.
> m->pctx->runtime = runtime;
> m->has_constraint = metric_no_group || metricgroup__has_constraint(pe);
> m->metric_refs = NULL;
> @@ -250,10 +256,12 @@ static bool contains_metric_id(struct evsel **metric_events, int num_events,
> * @ids: the metric IDs to match.
> * @metric_evlist: the list of perf events.
> * @out_metric_events: holds the created metric events array.
> + * @pmu_name: the name of the CPU.
Could pmu_name just be an optional PMU to be used for the events? We
don't need to be specific it is a CPU here?
> */
> static int setup_metric_events(struct hashmap *ids,
> struct evlist *metric_evlist,
> - struct evsel ***out_metric_events)
> + struct evsel ***out_metric_events,
> + const char *pmu_name)
> {
> struct evsel **metric_events;
> const char *metric_id;
> @@ -286,6 +294,10 @@ static int setup_metric_events(struct hashmap *ids,
> * about this event.
> */
> if (hashmap__find(ids, metric_id, (void **)&val_ptr)) {
> + if (evsel__is_hybrid(ev) && pmu_name &&
The evsel__is_hybrid looks unnecessary here.
> + strcmp(pmu_name, ev->pmu_name)) {
> + continue;
> + }
> metric_events[matched_events++] = ev;
>
> if (matched_events >= ids_size)
> @@ -724,7 +736,8 @@ static int decode_all_metric_ids(struct evlist *perf_evlist, const char *modifie
> static int metricgroup__build_event_string(struct strbuf *events,
> const struct expr_parse_ctx *ctx,
> const char *modifier,
> - bool has_constraint)
> + bool has_constraint,
> + const char *pmu_name)
> {
> struct hashmap_entry *cur;
> size_t bkt;
> @@ -806,12 +819,18 @@ static int metricgroup__build_event_string(struct strbuf *events,
> if (no_group) {
> /* Strange case of a metric of just duration_time. */
> ret = strbuf_addf(events, "duration_time");
> - } else if (!has_constraint)
> - ret = strbuf_addf(events, "}:W,duration_time");
> - else
> + } else if (!has_constraint) {
> + ret = strbuf_addf(events, "}:W");
> + if (pmu_name)
> + ret = strbuf_addf(events, "#%s", pmu_name);
> ret = strbuf_addf(events, ",duration_time");
> - } else if (!no_group && !has_constraint)
> + } else
> + ret = strbuf_addf(events, ",duration_time");
> + } else if (!no_group && !has_constraint) {
> ret = strbuf_addf(events, "}:W");
> + if (pmu_name)
> + ret = strbuf_addf(events, "#%s", pmu_name);
> + }
Why add the # and then expand it when you could just expand here?
> return ret;
> #undef RETURN_IF_NON_ZERO
> @@ -1150,11 +1169,13 @@ static int metric_list_cmp(void *priv __maybe_unused, const struct list_head *l,
> * @metric_list: The list that the metric or metric group are added to.
> * @map: The map that is searched for metrics, most commonly the table for the
> * architecture perf is running upon.
> + * @pmu_name: the name of the CPU.
> */
> -static int metricgroup__add_metric(const char *metric_name, const char *modifier,
> - bool metric_no_group,
> +static int metricgroup__add_metric(const char *metric_name,
> + const char *modifier, bool metric_no_group,
This is a whitespace only change.
> struct list_head *metric_list,
> - const struct pmu_events_map *map)
> + const struct pmu_events_map *map,
> + const char *pmu_name)
> {
> const struct pmu_event *pe;
> LIST_HEAD(list);
> @@ -1167,6 +1188,8 @@ static int metricgroup__add_metric(const char *metric_name, const char *modifier
> */
> map_for_each_metric(pe, i, map, metric_name) {
> has_match = true;
> + if (pmu_name && pe->pmu && strcmp(pmu_name, pe->pmu))
> + continue;
> ret = add_metric(&list, pe, modifier, metric_no_group,
> /*root_metric=*/NULL,
> /*visited_metrics=*/NULL, map);
> @@ -1215,10 +1238,12 @@ static int metricgroup__add_metric(const char *metric_name, const char *modifier
> * @metric_list: The list that metrics are added to.
> * @map: The map that is searched for metrics, most commonly the table for the
> * architecture perf is running upon.
> + * @pmu_name: the name of the CPU.
> */
> static int metricgroup__add_metric_list(const char *list, bool metric_no_group,
> struct list_head *metric_list,
> - const struct pmu_events_map *map)
> + const struct pmu_events_map *map,
> + const char *pmu_name)
> {
> char *list_itr, *list_copy, *metric_name, *modifier;
> int ret, count = 0;
> @@ -1235,7 +1260,7 @@ static int metricgroup__add_metric_list(const char *list, bool metric_no_group,
>
> ret = metricgroup__add_metric(metric_name, modifier,
> metric_no_group, metric_list,
> - map);
> + map, pmu_name);
> if (ret == -EINVAL)
> pr_err("Cannot find metric or group `%s'\n", metric_name);
>
> @@ -1310,6 +1335,183 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
> return ret;
> }
>
> +static char *get_metric_pmus(char *orig_str, struct strbuf *metric_pmus)
Could you add an example here. A metric is coming with an associated
PMU so what are we pulling out here? Why are the events modified? What
is the metric_pmus out argument doing?
> +{
> + char *llist, *nlist, *p1, *p2, *new_str = NULL;
> + int ret;
> + struct strbuf new_events;
> +
> + if (!strchr(orig_str, '#')) {
> + /*
> + * pmu name is added after '#'. If no '#' found,
> + * don't need to process pmu.
> + */
> + return strdup(orig_str);
> + }
> +
> + nlist = strdup(orig_str);
> + if (!nlist)
> + return new_str;
> +
> + ret = strbuf_init(&new_events, 100);
> + if (ret)
> + goto err_out;
> +
> + ret = strbuf_grow(metric_pmus, 100);
> + if (ret)
> + goto err_out;
> +
> + llist = nlist;
> + while ((p1 = strsep(&llist, ",")) != NULL) {
> + p2 = strchr(p1, '#');
> + if (p2) {
> + *p2 = 0;
> + ret = strbuf_addf(&new_events, "%s,", p1);
> + if (ret)
> + goto err_out;
> +
> + ret = strbuf_addf(metric_pmus, "%s,", p2 + 1);
> + if (ret)
> + goto err_out;
> +
> + } else {
> + ret = strbuf_addf(&new_events, "%s,", p1);
> + if (ret)
> + goto err_out;
> + }
> + }
> +
> + new_str = strdup(new_events.buf);
> + if (new_str) {
> + /* Remove last ',' */
> + new_str[strlen(new_str) - 1] = 0;
> + }
> +err_out:
> + free(nlist);
> + strbuf_release(&new_events);
> + return new_str;
> +}
> +
> +static void set_pmu_unmatched_events(struct evlist *evlist, int group_idx,
> + char *pmu_name,
> + unsigned long *evlist_removed)
> +{
> + struct evsel *evsel, *pos;
> + int i = 0, j = 0;
> +
> + /*
> + * Move to the first evsel of a given group
> + */
> + evlist__for_each_entry(evlist, evsel) {
> + if (evsel__is_group_leader(evsel) &&
> + evsel->core.nr_members >= 1) {
> + if (i < group_idx) {
> + j += evsel->core.nr_members;
> + i++;
> + continue;
> + }
> + }
> + }
> +
> + i = 0;
> + evlist__for_each_entry(evlist, evsel) {
> + if (i < j) {
> + i++;
> + continue;
> + }
> +
> + /*
> + * Now we are at the first evsel in the group
> + */
> + for_each_group_evsel(pos, evsel) {
> + if (evsel__is_hybrid(pos) &&
> + strcmp(pos->pmu_name, pmu_name)) {
> + set_bit(pos->core.idx, evlist_removed);
> + }
> + }
> + break;
> + }
> +}
> +
> +static void remove_pmu_umatched_events(struct evlist *evlist, char *metric_pmus)
Is it possible here that we have an evlist being used by >1 metric.
We've decided one of the metrics is invalid and set about removing the
events thereby breaking the other metric? In general this code treads
lightly around the evlist as previously it has been the source of
bugs:
https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/tools/perf/util/metricgroup.c?h=perf/core&id=5ecd5a0c7d1cca79f1431093d12e4cd9893b0331
> +{
> + struct evsel *evsel, *tmp, *new_leader = NULL;
> + unsigned long *evlist_removed;
> + char *llist, *nlist, *p1;
Is there a better name than nlist and llist? Could you explain what they mean?
> + bool need_new_leader = false;
> + int i = 0, new_nr_members = 0;
> +
> + nlist = strdup(metric_pmus);
> + if (!nlist)
> + return;
> +
> + evlist_removed = bitmap_zalloc(evlist->core.nr_entries);
> + if (!evlist_removed) {
> + free(nlist);
> + return;
> + }
> +
> + llist = nlist;
> + while ((p1 = strsep(&llist, ",")) != NULL) {
> + if (strlen(p1) > 0) {
> + /*
> + * p1 points to the string of pmu name, e.g. "cpu_atom".
> + * The metric group string has pmu suffixes, e.g.
> + * "{inst_retired.any,cpu_clk_unhalted.thread}:W#cpu_core,
> + * {cpu_clk_unhalted.core,inst_retired.any_p}:W#cpu_atom"
> + * By counting the pmu name, we can know the index of
> + * group.
> + */
> + set_pmu_unmatched_events(evlist, i++, p1,
> + evlist_removed);
> + }
> + }
> +
> + evlist__for_each_entry_safe(evlist, tmp, evsel) {
> + if (test_bit(evsel->core.idx, evlist_removed)) {
> + if (!evsel__is_group_leader(evsel)) {
> + if (!need_new_leader) {
> + if (new_leader)
> + new_leader->core.leader->nr_members--;
> + else
> + evsel->core.leader->nr_members--;
> + } else
> + new_nr_members--;
> + } else {
> + /*
> + * If group leader is to remove, we need to
> + * prepare a new leader and adjust all group
> + * members.
> + */
> + need_new_leader = true;
> + new_nr_members =
> + evsel->core.leader->nr_members - 1;
> + }
> +
> + evlist__remove(evlist, evsel);
> + evsel__delete(evsel);
> + } else {
> + if (!evsel__is_group_leader(evsel)) {
> + if (need_new_leader) {
> + need_new_leader = false;
> + new_leader = evsel;
> + new_leader->core.leader =
> + &new_leader->core;
> + new_leader->core.nr_members =
> + new_nr_members;
> + } else if (new_leader)
> + evsel->core.leader = &new_leader->core;
> + } else {
> + need_new_leader = false;
> + new_leader = NULL;
> + }
> + }
> + }
> +
> + bitmap_free(evlist_removed);
> + free(nlist);
> +}
> +
> /**
> * parse_ids - Build the event string for the ids and parse them creating an
> * evlist. The encoded metric_ids are decoded.
> @@ -1319,14 +1521,18 @@ static int build_combined_expr_ctx(const struct list_head *metric_list,
> * @modifier: any modifiers added to the events.
> * @has_constraint: false if events should be placed in a weak group.
> * @out_evlist: the created list of events.
> + * @pmu_name: the name of the CPU.
> */
> static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
> struct expr_parse_ctx *ids, const char *modifier,
> - bool has_constraint, struct evlist **out_evlist)
> + bool has_constraint, struct evlist **out_evlist,
> + const char *pmu_name)
> {
> struct parse_events_error parse_error;
> struct evlist *parsed_evlist;
> struct strbuf events = STRBUF_INIT;
> + struct strbuf metric_pmus = STRBUF_INIT;
> + char *nlist = NULL;
> int ret;
>
> *out_evlist = NULL;
> @@ -1353,7 +1559,7 @@ static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
> ids__insert(ids->ids, tmp);
> }
> ret = metricgroup__build_event_string(&events, ids, modifier,
> - has_constraint);
> + has_constraint, pmu_name);
> if (ret)
> return ret;
>
> @@ -1364,11 +1570,20 @@ static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
> }
> pr_debug("Parsing metric events '%s'\n", events.buf);
> parse_events_error__init(&parse_error);
> - ret = __parse_events(parsed_evlist, events.buf, &parse_error, fake_pmu);
> + nlist = get_metric_pmus(events.buf, &metric_pmus);
> + if (!nlist) {
> + ret = -ENOMEM;
> + goto err_out;
> + }
> + ret = __parse_events(parsed_evlist, nlist, &parse_error, fake_pmu);
> if (ret) {
> parse_events_error__print(&parse_error, events.buf);
> goto err_out;
> }
> +
> + if (metric_pmus.alloc)
> + remove_pmu_umatched_events(parsed_evlist, metric_pmus.buf);
> +
> ret = decode_all_metric_ids(parsed_evlist, modifier);
> if (ret)
> goto err_out;
> @@ -1376,9 +1591,12 @@ static int parse_ids(bool metric_no_merge, struct perf_pmu *fake_pmu,
> *out_evlist = parsed_evlist;
> parsed_evlist = NULL;
> err_out:
> + if (nlist)
> + free(nlist);
> parse_events_error__exit(&parse_error);
> evlist__delete(parsed_evlist);
> strbuf_release(&events);
> + strbuf_release(&metric_pmus);
> return ret;
> }
>
> @@ -1397,7 +1615,8 @@ static int parse_groups(struct evlist *perf_evlist, const char *str,
> if (metric_events_list->nr_entries == 0)
> metricgroup__rblist_init(metric_events_list);
> ret = metricgroup__add_metric_list(str, metric_no_group,
> - &metric_list, map);
> + &metric_list, map,
> + perf_evlist->hybrid_pmu_name);
This confuses me. perf_evlist is an out argument that we build the
list of evsels for the metrics into, yet here you are reading it for
the hybrid_pmu_name. Why is this? What values can hybrid_pmu_name be
here?
> if (ret)
> goto out;
>
> @@ -1413,7 +1632,8 @@ static int parse_groups(struct evlist *perf_evlist, const char *str,
> ret = parse_ids(metric_no_merge, fake_pmu, combined,
> /*modifier=*/NULL,
> /*has_constraint=*/true,
> - &combined_evlist);
> + &combined_evlist,
> + perf_evlist->hybrid_pmu_name);
I don't understand this. combined is a set of event names, it seems
now we need to combine the event name with the PMU to form an id.
> }
> if (combined)
> expr__ctx_free(combined);
> @@ -1450,6 +1670,9 @@ static int parse_groups(struct evlist *perf_evlist, const char *str,
> continue;
>
> if (expr__subset_of_ids(n->pctx, m->pctx)) {
> + if (m->pmu_name && n->pmu_name
> + && strcmp(m->pmu_name, n->pmu_name))
> + continue;
This test is cheaper than expr__subset_of_ids and should be before it.
> pr_debug("Events in '%s' fully contained within '%s'\n",
> m->metric_name, n->metric_name);
> metric_evlist = n->evlist;
> @@ -1459,14 +1682,16 @@ static int parse_groups(struct evlist *perf_evlist, const char *str,
> }
> }
> if (!metric_evlist) {
> - ret = parse_ids(metric_no_merge, fake_pmu, m->pctx, m->modifier,
> - m->has_constraint, &m->evlist);
> + ret = parse_ids(metric_no_merge, fake_pmu, m->pctx,
> + m->modifier, m->has_constraint,
> + &m->evlist, m->pmu_name);
> if (ret)
> goto out;
>
> metric_evlist = m->evlist;
> }
> - ret = setup_metric_events(m->pctx->ids, metric_evlist, &metric_events);
> + ret = setup_metric_events(m->pctx->ids, metric_evlist,
> + &metric_events, m->pmu_name);
> if (ret) {
> pr_debug("Cannot resolve IDs for %s: %s\n",
> m->metric_name, m->metric_expr);
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 138e3ab9d638..46b3dd134656 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -539,7 +539,8 @@ static void aggr_update_shadow(struct perf_stat_config *config,
> }
> }
>
> -static void uniquify_event_name(struct evsel *counter)
> +static void uniquify_event_name(struct evsel *counter,
> + struct perf_stat_config *stat_config)
> {
> char *new_name;
> char *config;
> @@ -558,7 +559,8 @@ static void uniquify_event_name(struct evsel *counter)
> counter->name = new_name;
> }
> } else {
> - if (perf_pmu__has_hybrid()) {
> + if (perf_pmu__has_hybrid() &&
> + stat_config->metric_events.nr_entries == 0) {
> ret = asprintf(&new_name, "%s/%s/",
> counter->pmu_name, counter->name);
> } else {
> @@ -619,7 +621,7 @@ static bool collect_data(struct perf_stat_config *config, struct evsel *counter,
> return false;
> cb(config, counter, data, true);
> if (config->no_merge || hybrid_uniquify(counter))
> - uniquify_event_name(counter);
> + uniquify_event_name(counter, config);
> else if (counter->auto_merge_stats)
> collect_all_aliases(config, counter, cb, data);
> return true;
> --
> 2.25.1
>
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