Re: [PATCH 12/36] libperf: Add perf_mmap__read_event() function

From: Arnaldo Carvalho de Melo
Date: Thu Oct 10 2019 - 10:47:09 EST

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Em Mon, Oct 07, 2019 at 02:53:20PM +0200, Jiri Olsa escreveu:
> Move perf_mmap__read_event() from tools/perf to libperf and export it in
> the perf/mmap.h header.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> Cc: Michael Petlan <mpetlan@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Link: http://lore.kernel.org/lkml/20190913132355.21634-52-jolsa@xxxxxxxxxx
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
> tools/perf/arch/x86/tests/perf-time-to-tsc.c | 2 +-
> tools/perf/builtin-kvm.c | 2 +-
> tools/perf/builtin-top.c | 2 +-
> tools/perf/builtin-trace.c | 2 +-
> tools/perf/lib/include/internal/mmap.h | 1 +
> tools/perf/lib/include/perf/mmap.h | 1 +
> tools/perf/lib/libperf.map | 1 +
> tools/perf/lib/mmap.c | 79 ++++++++++++++++++++
> tools/perf/tests/backward-ring-buffer.c | 2 +-
> tools/perf/tests/bpf.c | 2 +-
> tools/perf/tests/code-reading.c | 2 +-
> tools/perf/tests/keep-tracking.c | 2 +-
> tools/perf/tests/mmap-basic.c | 2 +-
> tools/perf/tests/openat-syscall-tp-fields.c | 2 +-
> tools/perf/tests/perf-record.c | 2 +-
> tools/perf/tests/sw-clock.c | 2 +-
> tools/perf/tests/switch-tracking.c | 2 +-
> tools/perf/tests/task-exit.c | 2 +-
> tools/perf/util/evlist.c | 2 +-
> tools/perf/util/mmap.c | 77 -------------------
> tools/perf/util/mmap.h | 2 -
> tools/perf/util/python.c | 2 +-
> 22 files changed, 98 insertions(+), 95 deletions(-)
>
> diff --git a/tools/perf/arch/x86/tests/perf-time-to-tsc.c b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
> index c90d925f7ae6..909ead08a6f6 100644
> --- a/tools/perf/arch/x86/tests/perf-time-to-tsc.c
> +++ b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
> @@ -121,7 +121,7 @@ int test__perf_time_to_tsc(struct test *test __maybe_unused, int subtest __maybe
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> struct perf_sample sample;
>
> if (event->header.type != PERF_RECORD_COMM ||
> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> index 4c087a8c9fed..858da896b518 100644
> --- a/tools/perf/builtin-kvm.c
> +++ b/tools/perf/builtin-kvm.c
> @@ -764,7 +764,7 @@ static s64 perf_kvm__mmap_read_idx(struct perf_kvm_stat *kvm, int idx,
> if (err < 0)
> return (err == -EAGAIN) ? 0 : -1;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> err = perf_evlist__parse_sample_timestamp(evlist, event, &timestamp);
> if (err) {
> perf_mmap__consume(&md->core);
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 1a54069ccd9c..d96f24c8770d 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -873,7 +873,7 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
> if (perf_mmap__read_init(&md->core) < 0)
> return;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> int ret;
>
> ret = perf_evlist__parse_sample_timestamp(evlist, event, &last_timestamp);
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 5fc3051a0938..2ae8298375a0 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -3454,7 +3454,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> ++trace->nr_events;
>
> err = trace__deliver_event(trace, event);
> diff --git a/tools/perf/lib/include/internal/mmap.h b/tools/perf/lib/include/internal/mmap.h
> index ee536c4441bb..b328332b6ccf 100644
> --- a/tools/perf/lib/include/internal/mmap.h
> +++ b/tools/perf/lib/include/internal/mmap.h
> @@ -11,6 +11,7 @@
> #define PERF_SAMPLE_MAX_SIZE (1 << 16)
>
> struct perf_mmap;
> +union perf_event;

Why are you adding this here?

> typedef void (*libperf_unmap_cb_t)(struct perf_mmap *map);
>
> diff --git a/tools/perf/lib/include/perf/mmap.h b/tools/perf/lib/include/perf/mmap.h
> index 4f946e7f724b..396c6543d95d 100644
> --- a/tools/perf/lib/include/perf/mmap.h
> +++ b/tools/perf/lib/include/perf/mmap.h
> @@ -9,5 +9,6 @@ struct perf_mmap;
> LIBPERF_API void perf_mmap__consume(struct perf_mmap *map);
> LIBPERF_API int perf_mmap__read_init(struct perf_mmap *map);
> LIBPERF_API void perf_mmap__read_done(struct perf_mmap *map);
> +LIBPERF_API union perf_event *perf_mmap__read_event(struct perf_mmap *map);
>
> #endif /* __LIBPERF_MMAP_H */
> diff --git a/tools/perf/lib/libperf.map b/tools/perf/lib/libperf.map
> index 7e3ea2e9c917..8bb0d73e0c6c 100644
> --- a/tools/perf/lib/libperf.map
> +++ b/tools/perf/lib/libperf.map
> @@ -43,6 +43,7 @@ LIBPERF_0.0.1 {
> perf_mmap__consume;
> perf_mmap__read_init;
> perf_mmap__read_done;
> + perf_mmap__read_event;
> local:
> *;
> };
> diff --git a/tools/perf/lib/mmap.c b/tools/perf/lib/mmap.c
> index 7d39289a4a22..fe9e1b095fd7 100644
> --- a/tools/perf/lib/mmap.c
> +++ b/tools/perf/lib/mmap.c
> @@ -3,9 +3,11 @@
> #include <inttypes.h>
> #include <asm/bug.h>
> #include <errno.h>
> +#include <string.h>
> #include <linux/ring_buffer.h>
> #include <linux/perf_event.h>
> #include <perf/mmap.h>
> +#include <perf/event.h>
> #include <internal/mmap.h>
> #include <internal/lib.h>
> #include "internal.h"
> @@ -191,3 +193,80 @@ void perf_mmap__read_done(struct perf_mmap *map)
>
> map->prev = perf_mmap__read_head(map);
> }
> +
> +/* When check_messup is true, 'end' must points to a good entry */
> +static union perf_event *perf_mmap__read(struct perf_mmap *map,
> + u64 *startp, u64 end)
> +{
> + unsigned char *data = map->base + page_size;
> + union perf_event *event = NULL;
> + int diff = end - *startp;
> +
> + if (diff >= (int)sizeof(event->header)) {
> + size_t size;
> +
> + event = (union perf_event *)&data[*startp & map->mask];
> + size = event->header.size;
> +
> + if (size < sizeof(event->header) || diff < (int)size)
> + return NULL;
> +
> + /*
> + * Event straddles the mmap boundary -- header should always
> + * be inside due to u64 alignment of output.
> + */
> + if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) {
> + unsigned int offset = *startp;
> + unsigned int len = min(sizeof(*event), size), cpy;
> + void *dst = map->event_copy;
> +
> + do {
> + cpy = min(map->mask + 1 - (offset & map->mask), len);
> + memcpy(dst, &data[offset & map->mask], cpy);
> + offset += cpy;
> + dst += cpy;
> + len -= cpy;
> + } while (len);
> +
> + event = (union perf_event *)map->event_copy;
> + }
> +
> + *startp += size;
> + }
> +
> + return event;
> +}
> +
> +/*
> + * Read event from ring buffer one by one.
> + * Return one event for each call.
> + *
> + * Usage:
> + * perf_mmap__read_init()
> + * while(event = perf_mmap__read_event()) {
> + * //process the event
> + * perf_mmap__consume()
> + * }
> + * perf_mmap__read_done()
> + */
> +union perf_event *perf_mmap__read_event(struct perf_mmap *map)
> +{
> + union perf_event *event;
> +
> + /*
> + * Check if event was unmapped due to a POLLHUP/POLLERR.
> + */
> + if (!refcount_read(&map->refcnt))
> + return NULL;
> +
> + /* non-overwirte doesn't pause the ringbuffer */
> + if (!map->overwrite)
> + map->end = perf_mmap__read_head(map);
> +
> + event = perf_mmap__read(map, &map->start, map->end);
> +
> + if (!map->overwrite)
> + map->prev = map->start;
> +
> + return event;
> +}
> diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
> index 13e67cd213bd..a4cd30c0beb3 100644
> --- a/tools/perf/tests/backward-ring-buffer.c
> +++ b/tools/perf/tests/backward-ring-buffer.c
> @@ -39,7 +39,7 @@ static int count_samples(struct evlist *evlist, int *sample_count,
> union perf_event *event;
>
> perf_mmap__read_init(&map->core);
> - while ((event = perf_mmap__read_event(map)) != NULL) {
> + while ((event = perf_mmap__read_event(&map->core)) != NULL) {
> const u32 type = event->header.type;
>
> switch (type) {
> diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
> index fd45529e29c1..5d20bf8397f0 100644
> --- a/tools/perf/tests/bpf.c
> +++ b/tools/perf/tests/bpf.c
> @@ -188,7 +188,7 @@ static int do_test(struct bpf_object *obj, int (*func)(void),
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> const u32 type = event->header.type;
>
> if (type == PERF_RECORD_SAMPLE)
> diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
> index 9947cda29bad..1f017e1b2a55 100644
> --- a/tools/perf/tests/code-reading.c
> +++ b/tools/perf/tests/code-reading.c
> @@ -429,7 +429,7 @@ static int process_events(struct machine *machine, struct evlist *evlist,
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> ret = process_event(machine, evlist, event, state);
> perf_mmap__consume(&md->core);
> if (ret < 0)
> diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
> index e950907f6f57..50a0c9fcde7d 100644
> --- a/tools/perf/tests/keep-tracking.c
> +++ b/tools/perf/tests/keep-tracking.c
> @@ -41,7 +41,7 @@ static int find_comm(struct evlist *evlist, const char *comm)
> md = &evlist->mmap[i];
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> if (event->header.type == PERF_RECORD_COMM &&
> (pid_t)event->comm.pid == getpid() &&
> (pid_t)event->comm.tid == getpid() &&
> diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
> index bb15d405a42c..5f4c0dbb4715 100644
> --- a/tools/perf/tests/mmap-basic.c
> +++ b/tools/perf/tests/mmap-basic.c
> @@ -117,7 +117,7 @@ int test__basic_mmap(struct test *test __maybe_unused, int subtest __maybe_unuse
> if (perf_mmap__read_init(&md->core) < 0)
> goto out_init;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> struct perf_sample sample;
>
> if (event->header.type != PERF_RECORD_SAMPLE) {
> diff --git a/tools/perf/tests/openat-syscall-tp-fields.c b/tools/perf/tests/openat-syscall-tp-fields.c
> index c95eb1bbf396..c6b2d7aab608 100644
> --- a/tools/perf/tests/openat-syscall-tp-fields.c
> +++ b/tools/perf/tests/openat-syscall-tp-fields.c
> @@ -96,7 +96,7 @@ int test__syscall_openat_tp_fields(struct test *test __maybe_unused, int subtest
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> const u32 type = event->header.type;
> int tp_flags;
> struct perf_sample sample;
> diff --git a/tools/perf/tests/perf-record.c b/tools/perf/tests/perf-record.c
> index 92a53be3b32b..2195fc205e72 100644
> --- a/tools/perf/tests/perf-record.c
> +++ b/tools/perf/tests/perf-record.c
> @@ -174,7 +174,7 @@ int test__PERF_RECORD(struct test *test __maybe_unused, int subtest __maybe_unus
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> const u32 type = event->header.type;
> const char *name = perf_event__name(type);
>
> diff --git a/tools/perf/tests/sw-clock.c b/tools/perf/tests/sw-clock.c
> index ace20921ad55..bfb9986093d8 100644
> --- a/tools/perf/tests/sw-clock.c
> +++ b/tools/perf/tests/sw-clock.c
> @@ -103,7 +103,7 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
> if (perf_mmap__read_init(&md->core) < 0)
> goto out_init;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> struct perf_sample sample;
>
> if (event->header.type != PERF_RECORD_SAMPLE)
> diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
> index 8400fb17c170..fcb0d03dba4e 100644
> --- a/tools/perf/tests/switch-tracking.c
> +++ b/tools/perf/tests/switch-tracking.c
> @@ -273,7 +273,7 @@ static int process_events(struct evlist *evlist,
> if (perf_mmap__read_init(&md->core) < 0)
> continue;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> cnt += 1;
> ret = add_event(evlist, &events, event);
> perf_mmap__consume(&md->core);
> diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c
> index c6a13948821c..4965f8b9055b 100644
> --- a/tools/perf/tests/task-exit.c
> +++ b/tools/perf/tests/task-exit.c
> @@ -121,7 +121,7 @@ int test__task_exit(struct test *test __maybe_unused, int subtest __maybe_unused
> if (perf_mmap__read_init(&md->core) < 0)
> goto out_init;
>
> - while ((event = perf_mmap__read_event(md)) != NULL) {
> + while ((event = perf_mmap__read_event(&md->core)) != NULL) {
> if (event->header.type == PERF_RECORD_EXIT)
> nr_exit++;
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 830dc91994bc..09fe8fe9805d 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1742,7 +1742,7 @@ static void *perf_evlist__poll_thread(void *arg)
>
> if (perf_mmap__read_init(&map->core))
> continue;
> - while ((event = perf_mmap__read_event(map)) != NULL) {
> + while ((event = perf_mmap__read_event(&map->core)) != NULL) {
> struct evsel *evsel = perf_evlist__event2evsel(evlist, event);
>
> if (evsel && evsel->side_band.cb)
> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> index 2dedef9b06fd..2a8bf0ab861c 100644
> --- a/tools/perf/util/mmap.c
> +++ b/tools/perf/util/mmap.c
> @@ -29,83 +29,6 @@ size_t mmap__mmap_len(struct mmap *map)
> return perf_mmap__mmap_len(&map->core);
> }
>
> -/* When check_messup is true, 'end' must points to a good entry */
> -static union perf_event *perf_mmap__read(struct mmap *map,
> - u64 *startp, u64 end)
> -{
> - unsigned char *data = map->core.base + page_size;
> - union perf_event *event = NULL;
> - int diff = end - *startp;
> -
> - if (diff >= (int)sizeof(event->header)) {
> - size_t size;
> -
> - event = (union perf_event *)&data[*startp & map->core.mask];
> - size = event->header.size;
> -
> - if (size < sizeof(event->header) || diff < (int)size)
> - return NULL;
> -
> - /*
> - * Event straddles the mmap boundary -- header should always
> - * be inside due to u64 alignment of output.
> - */
> - if ((*startp & map->core.mask) + size != ((*startp + size) & map->core.mask)) {
> - unsigned int offset = *startp;
> - unsigned int len = min(sizeof(*event), size), cpy;
> - void *dst = map->core.event_copy;
> -
> - do {
> - cpy = min(map->core.mask + 1 - (offset & map->core.mask), len);
> - memcpy(dst, &data[offset & map->core.mask], cpy);
> - offset += cpy;
> - dst += cpy;
> - len -= cpy;
> - } while (len);
> -
> - event = (union perf_event *)map->core.event_copy;
> - }
> -
> - *startp += size;
> - }
> -
> - return event;
> -}
> -
> -/*
> - * Read event from ring buffer one by one.
> - * Return one event for each call.
> - *
> - * Usage:
> - * perf_mmap__read_init()
> - * while(event = perf_mmap__read_event()) {
> - * //process the event
> - * perf_mmap__consume()
> - * }
> - * perf_mmap__read_done()
> - */
> -union perf_event *perf_mmap__read_event(struct mmap *map)
> -{
> - union perf_event *event;
> -
> - /*
> - * Check if event was unmapped due to a POLLHUP/POLLERR.
> - */
> - if (!refcount_read(&map->core.refcnt))
> - return NULL;
> -
> - /* non-overwirte doesn't pause the ringbuffer */
> - if (!map->core.overwrite)
> - map->core.end = perf_mmap__read_head(&map->core);
> -
> - event = perf_mmap__read(map, &map->core.start, map->core.end);
> -
> - if (!map->core.overwrite)
> - map->core.prev = map->core.start;
> -
> - return event;
> -}
> -
> int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
> struct auxtrace_mmap_params *mp __maybe_unused,
> void *userpg __maybe_unused,
> diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
> index 0b15702be1a5..bee4e83f7109 100644
> --- a/tools/perf/util/mmap.h
> +++ b/tools/perf/util/mmap.h
> @@ -47,8 +47,6 @@ void mmap__munmap(struct mmap *map);
>
> union perf_event *perf_mmap__read_forward(struct mmap *map);
>
> -union perf_event *perf_mmap__read_event(struct mmap *map);
> -
> int perf_mmap__push(struct mmap *md, void *to,
> int push(struct mmap *map, void *to, void *buf, size_t size));
>
> diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
> index 7cb432899e7a..78345442cad9 100644
> --- a/tools/perf/util/python.c
> +++ b/tools/perf/util/python.c
> @@ -1020,7 +1020,7 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
> if (perf_mmap__read_init(&md->core) < 0)
> goto end;
>
> - event = perf_mmap__read_event(md);
> + event = perf_mmap__read_event(&md->core);
> if (event != NULL) {
> PyObject *pyevent = pyrf_event__new(event);
> struct pyrf_event *pevent = (struct pyrf_event *)pyevent;
> --
> 2.21.0

--

- Arnaldo

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