Re: [PATCH v5 4/8] perf trace: Filter enum arguments with enum names

From: Howard Chu
Date: Thu Jul 11 2024 - 11:15:06 EST

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In reply to: Ian Rogers: "Re: [PATCH v5 4/8] perf trace: Filter enum arguments with enum names"
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Hello Ian,

On Thu, Jul 11, 2024 at 1:49 AM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> On Fri, Jul 5, 2024 at 2:43 AM Howard Chu <howardchu95@xxxxxxxxx> 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@xxxxxxxxxx>
> > Signed-off-by: Howard Chu <howardchu95@xxxxxxxxx>
> > Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> > Cc: Ian Rogers <irogers@xxxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/lkml/ZnCcliuecJABD5FN@x1
> > Link: https://lore.kernel.org/r/20240624181345.124764-5-howardchu95@xxxxxxxxx
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > ---
> > 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 for the review. I think these two lines are deleted from
Arnaldo's patch 'perf trace: Remove arg_fmt->is_enum, we can get that
from the BTF type
(b06414bc07f59ef0269ceb60a63126a01ab8018f)' that's done on top of this
patch, so I didn't pay too much attention to this, sorry for the
confusion. I will reorganize this patch series.

Thanks,
Howard
>
> 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
> >

Next message: Artem Sadovnikov: "[PATCH v5 5.10/5.15] ata: libata-scsi: check cdb length for VARIABLE_LENGTH_CMD commands"
Previous message: Anand Khoje: "[PATCH net-next] net/mlx5: Reclaim max 50K pages at once"
In reply to: Ian Rogers: "Re: [PATCH v5 4/8] perf trace: Filter enum arguments with enum names"
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