Re: [PATCH v1 2/3] perf tools: Revert enable indices setting syntax for BPF map

On 04/09/2023 15:56, Ian Rogers wrote:

On Mon, Sep 4, 2023 at 4:02 AM James Clark james.clark@arm.com wrote:

...

On 28/07/2023 01:12, Ian Rogers wrote:

...

This reverts commit e571e029bdbf ("perf tools: Enable indices setting syntax for BPF map").

The reverted commit added a notion of arrays that could be set as event terms for BPF events. The parsing hasn't worked over multiple Linux releases. Given the broken nature of the parsing it appears the code isn't in use, nor could I find a way for it to be used to add a test.

The original commit contains a test in the commit message, however, running it yields:

$ perf record -e './test_bpf_map_3.c/map:channel.value[0,1,2,3...5]=101/' usleep 2
event syntax error: '..pf_map_3.c/map:channel.value[0,1,2,3...5]=101/'
                                  \___ parser error
Run 'perf list' for a list of valid events

 Usage: perf record [<options>] [<command>]
    or: perf record [<options>] -- <command> [<options>]

    -e, --event <event>   event selector. use 'perf list' to list available events

Given the code can't be used this commit reverts and removes it.

Hi Ian,

Unfortunately this revert breaks Coresight sink argument parsing.

Before:

$ perf record -e cs_etm/@tmc_etr0/ -- true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 4.008 MB perf.data ]

After:

$ perf record -e cs_etm/@tmc_etr0/ -- true event syntax error: 'cs_etm/@tmc_etr0/' ___ parser error

I can't really see how it's related to the array syntax that the commit messages mention, but it could either be that the revert wasn't applied cleanly or just some unintended side effect.

We should probably add a cross platform parsing test for Coresight arguments, but I don't know whether we should just blindly revert the revert for now, or work on a new change that explicitly fixes the Coresight case.

Agreed, I'll take a look. Any chance you could post the full error message? I suspect there's a first error hiding in there too.

Thanks, Ian

No that seems to be the whole thing, running with -vvv and pasting everything:

$ perf record -e cs_etm/@tmc_etr0/ -vvv -- true event syntax error: 'cs_etm/@tmc_etr0/' ___ parser error Run 'perf list' for a list of valid events

Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>]

-e, --event <event> event selector. use 'perf list' to list available events

I previously mentioned that this is a Coresight thing, but I saw that it may actually be the more generic "drv_str". Unless nothing other than Coresight is using it, then it's just a Coresight thing.

...

Thanks James

...

Signed-off-by: Ian Rogers irogers@google.com

tools/perf/util/parse-events.c | 8 +-- tools/perf/util/parse-events.l | 11 --- tools/perf/util/parse-events.y | 122 --------------------------------- 3 files changed, 1 insertion(+), 140 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 02647313c918..0e2004511cf5 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -800,13 +800,7 @@ parse_events_config_bpf(struct parse_events_state *parse_state,

                  parse_events_error__handle(parse_state->error, idx,
                                          strdup(errbuf),

•                                         strdup(
  

-"Hint:\tValid config terms:\n" -" \tmap:[<arraymap>].value<indices>=[value]\n" -" \tmap:[<eventmap>].event<indices>=[event]\n" -"\n" -" \twhere <indices> is something like [0,3...5] or [all]\n" -" \t(add -v to see detail)"));

•                                         NULL);
                  return err;
          }
  }
  

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l index 99335ec586ae..d7d084cc4140 100644 --- a/tools/perf/util/parse-events.l +++ b/tools/perf/util/parse-events.l @@ -175,7 +175,6 @@ do { \ %x mem %s config %x event -%x array

group [^,{}/]*[{][^}]*[}][^,{}/]* event_pmu [^,{}/]+[/][^/]*[/][^,{}/]* @@ -251,14 +250,6 @@ non_digit [^0-9] } }

-<array>{ -"]" { BEGIN(config); return ']'; } -{num_dec} { return value(yyscanner, 10); } -{num_hex} { return value(yyscanner, 16); } -, { return ','; } -"..." { return PE_ARRAY_RANGE; } -}

<config>{ /* * Please update config_term_names when new static term is added. @@ -302,8 +293,6 @@ r0x{num_raw_hex} { return str(yyscanner, PE_RAW); } {lc_type}-{lc_op_result} { return lc_str(yyscanner, _parse_state); } {lc_type}-{lc_op_result}-{lc_op_result} { return lc_str(yyscanner, _parse_state); } {name_minus} { return str(yyscanner, PE_NAME); } -[all] { return PE_ARRAY_ALL; } -"[" { BEGIN(array); return '['; } @{drv_cfg_term} { return drv_str(yyscanner, PE_DRV_CFG_TERM); } }

diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y index 454577f7aff6..5a90e7874c59 100644 --- a/tools/perf/util/parse-events.y +++ b/tools/perf/util/parse-events.y @@ -64,7 +64,6 @@ static void free_list_evsel(struct list_head* list_evsel) %token PE_LEGACY_CACHE %token PE_PREFIX_MEM %token PE_ERROR -%token PE_ARRAY_ALL PE_ARRAY_RANGE %token PE_DRV_CFG_TERM %token PE_TERM_HW %type <num> PE_VALUE @@ -108,11 +107,6 @@ static void free_list_evsel(struct list_head* list_evsel) %type <list_evsel> groups %destructor { free_list_evsel ($$); } <list_evsel> %type <tracepoint_name> tracepoint_name -%destructor { free ($$.sys); free ($$.event); } <tracepoint_name> -%type <array> array -%type <array> array_term -%type <array> array_terms -%destructor { free ($$.ranges); } <array> %type <hardware_term> PE_TERM_HW %destructor { free ($$.str); } <hardware_term>

@@ -127,7 +121,6 @@ static void free_list_evsel(struct list_head* list_evsel) char *sys; char *event; } tracepoint_name;

• struct parse_events_array array;
  struct hardware_term {
          char *str;
          u64 num;
  

@@ -878,121 +871,6 @@ PE_TERM

  $$ = term;

} -| -name_or_raw array '=' name_or_legacy -{

• struct parse_events_term *term;
  

• int err = parse_events_term__str(&term, PARSE_EVENTS__TERM_TYPE_USER, $1, $4, &@1, &@4);
  

• if (err) {
  

•         free($1);
  

•         free($4);
  

•         free($2.ranges);
  

•         PE_ABORT(err);
  

• }
  

• term->array = $2;
  

• $$ = term;
  

-} -| -name_or_raw array '=' PE_VALUE -{

• struct parse_events_term *term;
  

• int err = parse_events_term__num(&term, PARSE_EVENTS__TERM_TYPE_USER, $1, $4, false, &@1, &@4);
  

• if (err) {
  

•         free($1);
  

•         free($2.ranges);
  

•         PE_ABORT(err);
  

• }
  

• term->array = $2;
  

• $$ = term;
  

-} -| -PE_DRV_CFG_TERM -{

• struct parse_events_term *term;
  

• char *config = strdup($1);
  

• int err;
  

• if (!config)
  

•         YYNOMEM;
  

• err = parse_events_term__str(&term, PARSE_EVENTS__TERM_TYPE_DRV_CFG, config, $1, &@1, NULL);
  

• if (err) {
  

•         free($1);
  

•         free(config);
  

•         PE_ABORT(err);
  

• }
  

• $$ = term;
  

-}

-array: -'[' array_terms ']' -{

• $$ = $2;
  

-} -| -PE_ARRAY_ALL -{

• $$.nr_ranges = 0;
  

• $$.ranges = NULL;
  

-}

-array_terms: -array_terms ',' array_term -{

• struct parse_events_array new_array;
  

• new_array.nr_ranges = $1.nr_ranges + $3.nr_ranges;
  

• new_array.ranges = realloc($1.ranges,
  

•                         sizeof(new_array.ranges[0]) *
  

•                         new_array.nr_ranges);
  

• if (!new_array.ranges)
  

•         YYNOMEM;
  

• memcpy(&new_array.ranges[$1.nr_ranges], $3.ranges,
  

•        $3.nr_ranges * sizeof(new_array.ranges[0]));
  

• free($3.ranges);
  

• $$ = new_array;
  

-} -| -array_term

-array_term: -PE_VALUE -{

• struct parse_events_array array;
  

• array.nr_ranges = 1;
  

• array.ranges = malloc(sizeof(array.ranges[0]));
  

• if (!array.ranges)
  

•         YYNOMEM;
  

• array.ranges[0].start = $1;
  

• array.ranges[0].length = 1;
  

• $$ = array;
  

-} -| -PE_VALUE PE_ARRAY_RANGE PE_VALUE -{

• struct parse_events_array array;
  

• if ($3 < $1) {
  

•         struct parse_events_state *parse_state = _parse_state;
  

•         struct parse_events_error *error = parse_state->error;
  

•         char *err_str;
  

•         if (asprintf(&err_str, "Expected '%ld' to be less-than '%ld'", $3, $1) < 0)
  

•                 err_str = NULL;
  

•         parse_events_error__handle(error, @1.first_column, err_str, NULL);
  

•         YYABORT;
  

• }
  

• array.nr_ranges = 1;
  

• array.ranges = malloc(sizeof(array.ranges[0]));
  

• if (!array.ranges)
  

•         YYNOMEM;
  

• array.ranges[0].start = $1;
  

• array.ranges[0].length = $3 - $1 + 1;
  

• $$ = array;
  

-}

sep_dc: ':' |