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Message-ID: <CAP-5=fVhPDuvJ7=H=BggPbYcT7WrD8-yG=czPjnNiXWvt_Etmg@mail.gmail.com>
Date: Wed, 10 Jul 2024 10:48:56 -0700
From: Ian Rogers <irogers@...gle.com>
To: Howard Chu <howardchu95@...il.com>
Cc: acme@...nel.org, adrian.hunter@...el.com, jolsa@...nel.org, 
	kan.liang@...ux.intel.com, namhyung@...nel.org, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Arnaldo Carvalho de Melo <acme@...hat.com>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Ingo Molnar <mingo@...hat.com>, Mark Rutland <mark.rutland@....com>, 
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH v5 4/8] perf trace: Filter enum arguments with enum names

On Fri, Jul 5, 2024 at 2:43 AM Howard Chu <howardchu95@...il.com> wrote:
>
> Before:
>
> perf $ ./perf trace -e timer:hrtimer_start --filter='mode!=HRTIMER_MODE_ABS_PINNED_HARD' --max-events=1
> No resolver (strtoul) for "mode" in "timer:hrtimer_start", can't set filter "(mode!=HRTIMER_MODE_ABS_PINNED_HARD) && (common_pid != 281988)"
>
> After:
>
> perf $ ./perf trace -e timer:hrtimer_start --filter='mode!=HRTIMER_MODE_ABS_PINNED_HARD' --max-events=1
>      0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff9498a6ca5f18, function: 0xffffffffa77a5be0, expires: 12351248764875, softexpires: 12351248764875, mode: HRTIMER_MODE_ABS)
>
> && and ||:
>
> perf $ ./perf trace -e timer:hrtimer_start --filter='mode != HRTIMER_MODE_ABS_PINNED_HARD && mode != HRTIMER_MODE_ABS' --max-events=1
>      0.000 Hyprland/534 timer:hrtimer_start(hrtimer: 0xffff9497801a84d0, function: 0xffffffffc04cdbe0, expires: 12639434638458, softexpires: 12639433638458, mode: HRTIMER_MODE_REL)
>
> perf $ ./perf trace -e timer:hrtimer_start --filter='mode == HRTIMER_MODE_REL || mode == HRTIMER_MODE_PINNED' --max-events=1
>      0.000 ldlck-test/60639 timer:hrtimer_start(hrtimer: 0xffffb16404ee7bf8, function: 0xffffffffa7790420, expires: 12772614418016, softexpires: 12772614368016, mode: HRTIMER_MODE_REL)
>
> Switching it up, using both enum name and integer value(--filter='mode == HRTIMER_MODE_ABS_PINNED_HARD || mode == 0'):
>
> perf $ ./perf trace -e timer:hrtimer_start --filter='mode == HRTIMER_MODE_ABS_PINNED_HARD || mode == 0' --max-events=3
>      0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff9498a6ca5f18, function: 0xffffffffa77a5be0, expires: 12601748739825, softexpires: 12601748739825, mode: HRTIMER_MODE_ABS_PINNED_HARD)
>      0.036 :0/0 timer:hrtimer_start(hrtimer: 0xffff9498a6ca5f18, function: 0xffffffffa77a5be0, expires: 12518758748124, softexpires: 12518758748124, mode: HRTIMER_MODE_ABS_PINNED_HARD)
>      0.172 tmux: server/41881 timer:hrtimer_start(hrtimer: 0xffffb164081e7838, function: 0xffffffffa7790420, expires: 12518768255836, softexpires: 12518768205836, mode: HRTIMER_MODE_ABS)
>
> P.S.
> perf $ pahole hrtimer_mode
> enum hrtimer_mode {
>         HRTIMER_MODE_ABS             = 0,
>         HRTIMER_MODE_REL             = 1,
>         HRTIMER_MODE_PINNED          = 2,
>         HRTIMER_MODE_SOFT            = 4,
>         HRTIMER_MODE_HARD            = 8,
>         HRTIMER_MODE_ABS_PINNED      = 2,
>         HRTIMER_MODE_REL_PINNED      = 3,
>         HRTIMER_MODE_ABS_SOFT        = 4,
>         HRTIMER_MODE_REL_SOFT        = 5,
>         HRTIMER_MODE_ABS_PINNED_SOFT = 6,
>         HRTIMER_MODE_REL_PINNED_SOFT = 7,
>         HRTIMER_MODE_ABS_HARD        = 8,
>         HRTIMER_MODE_REL_HARD        = 9,
>         HRTIMER_MODE_ABS_PINNED_HARD = 10,
>         HRTIMER_MODE_REL_PINNED_HARD = 11,
> };
>
> Committer testing:
>
>   root@x1:~# perf trace -e timer:hrtimer_start --filter='mode != HRTIMER_MODE_ABS' --max-events=2
>        0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff8d4eff2a5050, function: 0xffffffff9e22ddd0, expires: 241502326000000, softexpires: 241502326000000, mode: HRTIMER_MODE_ABS_PINNED_HARD)
>   18446744073709.488 :0/0 timer:hrtimer_start(hrtimer: 0xffff8d4eff425050, function: 0xffffffff9e22ddd0, expires: 241501814000000, softexpires: 241501814000000, mode: HRTIMER_MODE_ABS_PINNED_HARD)
>   root@x1:~# perf trace -e timer:hrtimer_start --filter='mode != HRTIMER_MODE_ABS && mode != HRTIMER_MODE_ABS_PINNED_HARD' --max-events=2
>        0.000 podman/510644 timer:hrtimer_start(hrtimer: 0xffffa2024f5f7dd0, function: 0xffffffff9e2170c0, expires: 241530497418194, softexpires: 241530497368194, mode: HRTIMER_MODE_REL)
>       40.251 gnome-shell/2484 timer:hrtimer_start(hrtimer: 0xffff8d48bda17650, function: 0xffffffffc0661550, expires: 241550528619247, softexpires: 241550527619247, mode: HRTIMER_MODE_REL)
>   root@x1:~# perf trace -v -e timer:hrtimer_start --filter='mode != HRTIMER_MODE_ABS && mode != HRTIMER_MODE_ABS_PINNED_HARD && mode != HRTIMER_MODE_REL' --max-events=2
>   Using CPUID GenuineIntel-6-BA-3
>   vmlinux BTF loaded
>   <SNIP>
>   0
>   0xa
>   0x1
>   New filter for timer:hrtimer_start: (mode != 0 && mode != 0xa && mode != 0x1) && (common_pid != 524049 && common_pid != 4041)
>   mmap size 528384B
>   ^Croot@x1:~#
>
> Suggested-by: Arnaldo Carvalho de Melo <acme@...nel.org>
> Signed-off-by: Howard Chu <howardchu95@...il.com>
> Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Ian Rogers <irogers@...gle.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Kan Liang <kan.liang@...ux.intel.com>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Link: https://lore.kernel.org/lkml/ZnCcliuecJABD5FN@x1
> Link: https://lore.kernel.org/r/20240624181345.124764-5-howardchu95@gmail.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
>  tools/perf/builtin-trace.c | 62 ++++++++++++++++++++++++++++++++++----
>  1 file changed, 56 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 5618feb7d01a..e664001d5ed7 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -932,6 +932,37 @@ static int syscall_arg_fmt__cache_btf_enum(struct syscall_arg_fmt *arg_fmt, stru
>         return arg_fmt->type == NULL ? -1 : 0;
>  }
>
> +static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_arg *arg, u64 *val)
> +{
> +       const struct btf_type *bt;
> +       char *type = arg->parm;
> +       struct btf_enum *be;
> +       struct btf *btf;
> +
> +       trace__load_vmlinux_btf(arg->trace);
> +
> +       btf = arg->trace->btf;
> +       if (btf == NULL)
> +               return false;
> +
> +       if (syscall_arg_fmt__cache_btf_enum(arg->fmt, btf, type) < 0)
> +               return false;
> +
> +       bt = arg->fmt->type;
> +       be = btf_enum(bt);
> +       for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
> +               const char *name = btf__name_by_offset(btf, be->name_off);
> +               int max_len = max(size, strlen(name));
> +
> +               if (strncmp(name, bf, max_len) == 0) {
> +                       *val = be->val;
> +                       return true;
> +               }
> +       }
> +
> +       return false;
> +}
> +
>  static size_t btf_enum_scnprintf(const struct btf_type *type, struct btf *btf, char *bf, size_t size, int val)
>  {
>         struct btf_enum *be = btf_enum(type);
> @@ -965,8 +996,16 @@ static size_t trace__btf_enum_scnprintf(struct trace *trace __maybe_unused, stru
>  {
>         return 0;
>  }
> +
> +static bool syscall_arg__strtoul_btf_enum(char *bf __maybe_unused, size_t size __maybe_unused,
> +                                         struct syscall_arg *arg __maybe_unused, u64 *val __maybe_unused)
> +{
> +       return false;
> +}
>  #endif // HAVE_LIBBPF_SUPPORT
>
> +#define STUL_BTF_ENUM syscall_arg__strtoul_btf_enum
> +
>  #define STRARRAY(name, array) \
>           { .scnprintf  = SCA_STRARRAY, \
>             .strtoul    = STUL_STRARRAY, \
> @@ -1867,6 +1906,7 @@ syscall_arg_fmt__init_array(struct syscall_arg_fmt *arg, struct tep_format_field
>                         arg->scnprintf = SCA_FD;
>                 } else if (strstr(field->type, "enum") && use_btf != NULL) {
>                         *use_btf = arg->is_enum = true;
> +                       arg->strtoul = STUL_BTF_ENUM;
>                 } else {
>                         const struct syscall_arg_fmt *fmt =
>                                 syscall_arg_fmt__find_by_name(field->name);
> @@ -3792,7 +3832,8 @@ static int ordered_events__deliver_event(struct ordered_events *oe,
>         return __trace__deliver_event(trace, event->event);
>  }
>
> -static struct syscall_arg_fmt *evsel__find_syscall_arg_fmt_by_name(struct evsel *evsel, char *arg)
> +static struct syscall_arg_fmt *evsel__find_syscall_arg_fmt_by_name(struct evsel *evsel, char *arg,
> +                                                                  char **type)
>  {
>         struct tep_format_field *field;
>         struct syscall_arg_fmt *fmt = __evsel__syscall_arg_fmt(evsel);
> @@ -3801,13 +3842,15 @@ static struct syscall_arg_fmt *evsel__find_syscall_arg_fmt_by_name(struct evsel
>                 return NULL;
>
>         for (field = evsel->tp_format->format.fields; field; field = field->next, ++fmt)
> -               if (strcmp(field->name, arg) == 0)
> +               if (strcmp(field->name, arg) == 0) {
> +                       *type = field->type;
>                         return fmt;
> +               }
>
>         return NULL;
>  }
>
> -static int trace__expand_filter(struct trace *trace __maybe_unused, struct evsel *evsel)
> +static int trace__expand_filter(struct trace *trace, struct evsel *evsel)
>  {
>         char *tok, *left = evsel->filter, *new_filter = evsel->filter;
>
> @@ -3840,14 +3883,14 @@ static int trace__expand_filter(struct trace *trace __maybe_unused, struct evsel
>                         struct syscall_arg_fmt *fmt;
>                         int left_size = tok - left,
>                             right_size = right_end - right;
> -                       char arg[128];
> +                       char arg[128], *type;
>
>                         while (isspace(left[left_size - 1]))
>                                 --left_size;
>
>                         scnprintf(arg, sizeof(arg), "%.*s", left_size, left);
>
> -                       fmt = evsel__find_syscall_arg_fmt_by_name(evsel, arg);
> +                       fmt = evsel__find_syscall_arg_fmt_by_name(evsel, arg, &type);
>                         if (fmt == NULL) {
>                                 pr_err("\"%s\" not found in \"%s\", can't set filter \"%s\"\n",
>                                        arg, evsel->name, evsel->filter);
> @@ -3860,9 +3903,16 @@ static int trace__expand_filter(struct trace *trace __maybe_unused, struct evsel
>                         if (fmt->strtoul) {
>                                 u64 val;
>                                 struct syscall_arg syscall_arg = {
> -                                       .parm = fmt->parm,
> +                                       .trace = trace,
> +                                       .fmt   = fmt,
>                                 };
>
> +                               if (fmt->is_enum) {
> +                                       syscall_arg.parm = type;
> +                               } else {
> +                                       syscall_arg.parm = fmt->parm;
> +                               }

Hi Howard,

minor nit that cases like this shouldn't use curly braces as per:
https://www.kernel.org/doc/html/v4.10/process/coding-style.html#placing-braces-and-spaces

Thanks,
Ian

> +
>                                 if (fmt->strtoul(right, right_size, &syscall_arg, &val)) {
>                                         char *n, expansion[19];
>                                         int expansion_lenght = scnprintf(expansion, sizeof(expansion), "%#" PRIx64, val);
> --
> 2.45.2
>

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