Re: [PATCH v8 4/7] perf/tools: Enhance JSON/metric infrastructure to handle "?"

[Ian Rogers]

On Wed, Apr 1, 2020 at 1:35 PM Kajol Jain <kjain@xxxxxxxxxxxxx> wrote:
>
> Patch enhances current metric infrastructure to handle "?" in the metric
> expression. The "?" can be use for parameters whose value not known while
> creating metric events and which can be replace later at runtime to
> the proper value. It also add flexibility to create multiple events out
> of single metric event added in json file.
>
> Patch adds function 'arch_get_runtimeparam' which is a arch specific
> function, returns the count of metric events need to be created.
> By default it return 1.

Sorry for the slow response, I was trying to understand this patch in
relation to the PMU aliases to see if there was an overlap - I'm still
not sure. This is now merged so I'm just commenting wrt possible
future cleanup. I defer to the maintainers on how this should be
organized. At the metric level, this problem reminds me of both
#smt_on and LLC_MISSES.PCIE_WRITE on cascade lake. #smt_on adds a
degree of CPU specific behavior to an expression.
LLC_MISSES.PCIE_WRITE uses .part0 ... part3 to combine separate but
related counters.
The symbols that the metrics parse are then passed to parse-event. You
don't change parse-event as metricgroup replaces the '?' with a read
value from /devices/hv_24x7/interface/sockets, actually 0 to that
value-1 are passed.

It seems unfortunate to overload the meaning of runtime with a value
read from /devices/hv_24x7/interface/sockets and plumbing this value
around is quite a bit of noise for everything but this use-case. I
kind of wish we could do something like:

for i in 0, read("/devices/hv_24x7/interface/sockets"):
  hv_24x7/pm_pb_cyc,chip=$i

in the metric code. I have some patches to send related to metric
groups and I think this will be an active area of development for a
while as I think there are some open questions on the organization of
the code.

Thanks,
Ian

> This infrastructure needed for hv_24x7 socket/chip level events.
> "hv_24x7" chip level events needs specific chip-id to which the
> data is requested. Function 'arch_get_runtimeparam' implemented
> in header.c which extract number of sockets from sysfs file
> "sockets" under "/sys/devices/hv_24x7/interface/".
>
> With this patch basically we are trying to create as many metric events
> as define by runtime_param.
>
> For that one loop is added in function 'metricgroup__add_metric',
> which create multiple events at run time depend on return value of
> 'arch_get_runtimeparam' and merge that event in 'group_list'.
>
> To achieve that we are actually passing this parameter value as part of
> `expr__find_other` function and changing "?" present in metric expression
> with this value.
>
> As in our json file, there gonna be single metric event, and out of
> which we are creating multiple events.
>
> To understand which data count belongs to which parameter value,
> we also printing param value in generic_metric function.
>
> For example,
> command:# ./perf stat  -M PowerBUS_Frequency -C 0 -I 1000
>      1.000101867          9,356,933      hv_24x7/pm_pb_cyc,chip=0/ #      2.3 GHz  PowerBUS_Frequency_0
>      1.000101867          9,366,134      hv_24x7/pm_pb_cyc,chip=1/ #      2.3 GHz  PowerBUS_Frequency_1
>      2.000314878          9,365,868      hv_24x7/pm_pb_cyc,chip=0/ #      2.3 GHz  PowerBUS_Frequency_0
>      2.000314878          9,366,092      hv_24x7/pm_pb_cyc,chip=1/ #      2.3 GHz  PowerBUS_Frequency_1
>
> So, here _0 and _1 after PowerBUS_Frequency specify parameter value.
>
> Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
> ---
>  tools/perf/arch/powerpc/util/header.c |  8 ++++++++
>  tools/perf/tests/expr.c               |  8 ++++----
>  tools/perf/util/expr.c                | 11 ++++++-----
>  tools/perf/util/expr.h                |  5 +++--
>  tools/perf/util/expr.l                | 27 +++++++++++++++++++-------
>  tools/perf/util/metricgroup.c         | 28 ++++++++++++++++++++++++---
>  tools/perf/util/metricgroup.h         |  2 ++
>  tools/perf/util/stat-shadow.c         | 17 ++++++++++------
>  8 files changed, 79 insertions(+), 27 deletions(-)
>
> diff --git a/tools/perf/arch/powerpc/util/header.c b/tools/perf/arch/powerpc/util/header.c
> index 3b4cdfc5efd6..d4870074f14c 100644
> --- a/tools/perf/arch/powerpc/util/header.c
> +++ b/tools/perf/arch/powerpc/util/header.c
> @@ -7,6 +7,8 @@
>  #include <string.h>
>  #include <linux/stringify.h>
>  #include "header.h"
> +#include "metricgroup.h"
> +#include <api/fs/fs.h>
>
>  #define mfspr(rn)       ({unsigned long rval; \
>                          asm volatile("mfspr %0," __stringify(rn) \
> @@ -44,3 +46,9 @@ get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
>
>         return bufp;
>  }
> +
> +int arch_get_runtimeparam(void)
> +{
> +       int count;
> +       return sysfs__read_int("/devices/hv_24x7/interface/sockets", &count) < 0 ? 1 : count;
> +}
> diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
> index ea10fc4412c4..516504cf0ea5 100644
> --- a/tools/perf/tests/expr.c
> +++ b/tools/perf/tests/expr.c
> @@ -10,7 +10,7 @@ static int test(struct expr_parse_ctx *ctx, const char *e, double val2)
>  {
>         double val;
>
> -       if (expr__parse(&val, ctx, e))
> +       if (expr__parse(&val, ctx, e, 1))
>                 TEST_ASSERT_VAL("parse test failed", 0);
>         TEST_ASSERT_VAL("unexpected value", val == val2);
>         return 0;
> @@ -44,15 +44,15 @@ int test__expr(struct test *t __maybe_unused, int subtest __maybe_unused)
>                 return ret;
>
>         p = "FOO/0";
> -       ret = expr__parse(&val, &ctx, p);
> +       ret = expr__parse(&val, &ctx, p, 1);
>         TEST_ASSERT_VAL("division by zero", ret == -1);
>
>         p = "BAR/";
> -       ret = expr__parse(&val, &ctx, p);
> +       ret = expr__parse(&val, &ctx, p, 1);
>         TEST_ASSERT_VAL("missing operand", ret == -1);
>
>         TEST_ASSERT_VAL("find other",
> -                       expr__find_other("FOO + BAR + BAZ + BOZO", "FOO", &other, &num_other) == 0);
> +                       expr__find_other("FOO + BAR + BAZ + BOZO", "FOO", &other, &num_other, 1) == 0);
>         TEST_ASSERT_VAL("find other", num_other == 3);
>         TEST_ASSERT_VAL("find other", !strcmp(other[0], "BAR"));
>         TEST_ASSERT_VAL("find other", !strcmp(other[1], "BAZ"));
> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index c3382d58cf40..aa631e37ad1e 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -27,10 +27,11 @@ void expr__ctx_init(struct expr_parse_ctx *ctx)
>
>  static int
>  __expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
> -             int start)
> +             int start, int runtime)
>  {
>         struct expr_scanner_ctx scanner_ctx = {
>                 .start_token = start,
> +               .runtime = runtime,
>         };
>         YY_BUFFER_STATE buffer;
>         void *scanner;
> @@ -54,9 +55,9 @@ __expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
>         return ret;
>  }
>
> -int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr)
> +int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr, int runtime)
>  {
> -       return __expr__parse(final_val, ctx, expr, EXPR_PARSE) ? -1 : 0;
> +       return __expr__parse(final_val, ctx, expr, EXPR_PARSE, runtime) ? -1 : 0;
>  }
>
>  static bool
> @@ -74,13 +75,13 @@ already_seen(const char *val, const char *one, const char **other,
>  }
>
>  int expr__find_other(const char *expr, const char *one, const char ***other,
> -                    int *num_other)
> +                    int *num_other, int runtime)
>  {
>         int err, i = 0, j = 0;
>         struct expr_parse_ctx ctx;
>
>         expr__ctx_init(&ctx);
> -       err = __expr__parse(NULL, &ctx, expr, EXPR_OTHER);
> +       err = __expr__parse(NULL, &ctx, expr, EXPR_OTHER, runtime);
>         if (err)
>                 return -1;
>
> diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
> index 0938ad166ece..87d627bb699b 100644
> --- a/tools/perf/util/expr.h
> +++ b/tools/perf/util/expr.h
> @@ -17,12 +17,13 @@ struct expr_parse_ctx {
>
>  struct expr_scanner_ctx {
>         int start_token;
> +       int runtime;
>  };
>
>  void expr__ctx_init(struct expr_parse_ctx *ctx);
>  void expr__add_id(struct expr_parse_ctx *ctx, const char *id, double val);
> -int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr);
> +int expr__parse(double *final_val, struct expr_parse_ctx *ctx, const char *expr, int runtime);
>  int expr__find_other(const char *expr, const char *one, const char ***other,
> -               int *num_other);
> +               int *num_other, int runtime);
>
>  #endif
> diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
> index 2582c2464938..74b9b59b1aa5 100644
> --- a/tools/perf/util/expr.l
> +++ b/tools/perf/util/expr.l
> @@ -35,7 +35,7 @@ static int value(yyscan_t scanner, int base)
>   * Allow @ instead of / to be able to specify pmu/event/ without
>   * conflicts with normal division.
>   */
> -static char *normalize(char *str)
> +static char *normalize(char *str, int runtime)
>  {
>         char *ret = str;
>         char *dst = str;
> @@ -45,6 +45,19 @@ static char *normalize(char *str)
>                         *dst++ = '/';
>                 else if (*str == '\\')
>                         *dst++ = *++str;
> +                else if (*str == '?') {
> +                       char *paramval;
> +                       int i = 0;
> +                       int size = asprintf(&paramval, "%d", runtime);
> +
> +                       if (size < 0)
> +                               *dst++ = '0';
> +                       else {
> +                               while (i < size)
> +                                       *dst++ = paramval[i++];
> +                               free(paramval);
> +                       }
> +               }
>                 else
>                         *dst++ = *str;
>                 str++;
> @@ -54,16 +67,16 @@ static char *normalize(char *str)
>         return ret;
>  }
>
> -static int str(yyscan_t scanner, int token)
> +static int str(yyscan_t scanner, int token, int runtime)
>  {
>         YYSTYPE *yylval = expr_get_lval(scanner);
>         char *text = expr_get_text(scanner);
>
> -       yylval->str = normalize(strdup(text));
> +       yylval->str = normalize(strdup(text), runtime);
>         if (!yylval->str)
>                 return EXPR_ERROR;
>
> -       yylval->str = normalize(yylval->str);
> +       yylval->str = normalize(yylval->str, runtime);
>         return token;
>  }
>  %}
> @@ -72,8 +85,8 @@ number                [0-9]+
>
>  sch            [-,=]
>  spec           \\{sch}
> -sym            [0-9a-zA-Z_\.:@]+
> -symbol         {spec}*{sym}*{spec}*{sym}*
> +sym            [0-9a-zA-Z_\.:@?]+
> +symbol         {spec}*{sym}*{spec}*{sym}*{spec}*{sym}
>
>  %%
>         struct expr_scanner_ctx *sctx = expr_get_extra(yyscanner);
> @@ -93,7 +106,7 @@ if           { return IF; }
>  else           { return ELSE; }
>  #smt_on                { return SMT_ON; }
>  {number}       { return value(yyscanner, 10); }
> -{symbol}       { return str(yyscanner, ID); }
> +{symbol}       { return str(yyscanner, ID, sctx->runtime); }
>  "|"            { return '|'; }
>  "^"            { return '^'; }
>  "&"            { return '&'; }
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 7ad81c8177ea..b071df373f8b 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -90,6 +90,7 @@ struct egroup {
>         const char *metric_name;
>         const char *metric_expr;
>         const char *metric_unit;
> +       int runtime;
>  };
>
>  static struct evsel *find_evsel_group(struct evlist *perf_evlist,
> @@ -202,6 +203,7 @@ static int metricgroup__setup_events(struct list_head *groups,
>                 expr->metric_name = eg->metric_name;
>                 expr->metric_unit = eg->metric_unit;
>                 expr->metric_events = metric_events;
> +               expr->runtime = eg->runtime;
>                 list_add(&expr->nd, &me->head);
>         }
>
> @@ -485,15 +487,20 @@ static bool metricgroup__has_constraint(struct pmu_event *pe)
>         return false;
>  }
>
> +int __weak arch_get_runtimeparam(void)
> +{
> +       return 1;
> +}
> +
>  static int __metricgroup__add_metric(struct strbuf *events,
> -                       struct list_head *group_list, struct pmu_event *pe)
> +               struct list_head *group_list, struct pmu_event *pe, int runtime)
>  {
>
>         const char **ids;
>         int idnum;
>         struct egroup *eg;
>
> -       if (expr__find_other(pe->metric_expr, NULL, &ids, &idnum) < 0)
> +       if (expr__find_other(pe->metric_expr, NULL, &ids, &idnum, runtime) < 0)
>                 return -EINVAL;
>
>         if (events->len > 0)
> @@ -513,6 +520,7 @@ static int __metricgroup__add_metric(struct strbuf *events,
>         eg->metric_name = pe->metric_name;
>         eg->metric_expr = pe->metric_expr;
>         eg->metric_unit = pe->unit;
> +       eg->runtime = runtime;
>         list_add_tail(&eg->nd, group_list);
>
>         return 0;
> @@ -540,7 +548,21 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
>
>                         pr_debug("metric expr %s for %s\n", pe->metric_expr, pe->metric_name);
>
> -                       ret = __metricgroup__add_metric(events, group_list, pe);
> +                       if (!strstr(pe->metric_expr, "?")) {
> +                               ret = __metricgroup__add_metric(events, group_list, pe, 1);
> +                       } else {
> +                               int j, count;
> +
> +                               count = arch_get_runtimeparam();
> +
> +                               /* This loop is added to create multiple
> +                                * events depend on count value and add
> +                                * those events to group_list.
> +                                */
> +
> +                               for (j = 0; j < count; j++)
> +                                       ret = __metricgroup__add_metric(events, group_list, pe, j);
> +                       }
>                         if (ret == -ENOMEM)
>                                 break;
>                 }
> diff --git a/tools/perf/util/metricgroup.h b/tools/perf/util/metricgroup.h
> index 475c7f912864..6b09eb30b4ec 100644
> --- a/tools/perf/util/metricgroup.h
> +++ b/tools/perf/util/metricgroup.h
> @@ -22,6 +22,7 @@ struct metric_expr {
>         const char *metric_name;
>         const char *metric_unit;
>         struct evsel **metric_events;
> +       int runtime;
>  };
>
>  struct metric_event *metricgroup__lookup(struct rblist *metric_events,
> @@ -34,4 +35,5 @@ int metricgroup__parse_groups(const struct option *opt,
>  void metricgroup__print(bool metrics, bool groups, char *filter,
>                         bool raw, bool details);
>  bool metricgroup__has_metric(const char *metric);
> +int arch_get_runtimeparam(void);
>  #endif
> diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
> index 402af3e8d287..cf353ca591a5 100644
> --- a/tools/perf/util/stat-shadow.c
> +++ b/tools/perf/util/stat-shadow.c
> @@ -336,7 +336,7 @@ void perf_stat__collect_metric_expr(struct evlist *evsel_list)
>                 metric_events = counter->metric_events;
>                 if (!metric_events) {
>                         if (expr__find_other(counter->metric_expr, counter->name,
> -                                               &metric_names, &num_metric_names) < 0)
> +                                               &metric_names, &num_metric_names, 1) < 0)
>                                 continue;
>
>                         metric_events = calloc(sizeof(struct evsel *),
> @@ -723,6 +723,7 @@ static void generic_metric(struct perf_stat_config *config,
>                            char *name,
>                            const char *metric_name,
>                            const char *metric_unit,
> +                          int runtime,
>                            double avg,
>                            int cpu,
>                            struct perf_stat_output_ctx *out,
> @@ -777,7 +778,7 @@ static void generic_metric(struct perf_stat_config *config,
>         }
>
>         if (!metric_events[i]) {
> -               if (expr__parse(&ratio, &pctx, metric_expr) == 0) {
> +               if (expr__parse(&ratio, &pctx, metric_expr, runtime) == 0) {
>                         char *unit;
>                         char metric_bf[64];
>
> @@ -786,9 +787,13 @@ static void generic_metric(struct perf_stat_config *config,
>                                         &unit, &scale) >= 0) {
>                                         ratio *= scale;
>                                 }
> -
> -                               scnprintf(metric_bf, sizeof(metric_bf),
> +                               if (strstr(metric_expr, "?"))
> +                                       scnprintf(metric_bf, sizeof(metric_bf),
> +                                         "%s  %s_%d", unit, metric_name, runtime);
> +                               else
> +                                       scnprintf(metric_bf, sizeof(metric_bf),
>                                           "%s  %s", unit, metric_name);
> +
>                                 print_metric(config, ctxp, NULL, "%8.1f",
>                                              metric_bf, ratio);
>                         } else {
> @@ -1019,7 +1024,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
>                         print_metric(config, ctxp, NULL, NULL, name, 0);
>         } else if (evsel->metric_expr) {
>                 generic_metric(config, evsel->metric_expr, evsel->metric_events, evsel->name,
> -                               evsel->metric_name, NULL, avg, cpu, out, st);
> +                               evsel->metric_name, NULL, 1, avg, cpu, out, st);
>         } else if (runtime_stat_n(st, STAT_NSECS, 0, cpu) != 0) {
>                 char unit = 'M';
>                 char unit_buf[10];
> @@ -1048,7 +1053,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
>                                 out->new_line(config, ctxp);
>                         generic_metric(config, mexp->metric_expr, mexp->metric_events,
>                                         evsel->name, mexp->metric_name,
> -                                       mexp->metric_unit, avg, cpu, out, st);
> +                                       mexp->metric_unit, mexp->runtime, avg, cpu, out, st);
>                 }
>         }
>         if (num == 0)
> --
> 2.21.0
>