Re: [PATCH 15/26] perf tools: Synthesize proc tasks with mmap3

Arnaldo Carvalho de Melo
2020-09-14T16:11:39Z

Em Sun, Sep 13, 2020 at 11:03:02PM +0200, Jiri Olsa escreveu:
> Synthesizing proc tasks with mmap3 events so we can
> get build id data for synthesized maps as well.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/mmap.c | 2 +-
> tools/perf/util/synthetic-events.c | 72 +++++++++++++++++-------------
> 2 files changed, 43 insertions(+), 31 deletions(-)
>
> diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> index ab7108d22428..51f6f86580a9 100644
> --- a/tools/perf/util/mmap.c
> +++ b/tools/perf/util/mmap.c
> @@ -33,7 +33,7 @@ void mmap_cpu_mask__scnprintf(struct mmap_cpu_mask *mask, const char *tag)
>
> len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE);
> buf[len] = '\0';
> - pr_debug("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf);
> + pr_debug2("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf);
> }

Can this be in a separate patch?

> size_t mmap__mmap_len(struct mmap *map)
> diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
> index 89b390623b63..bd6e7b84283d 100644
> --- a/tools/perf/util/synthetic-events.c
> +++ b/tools/perf/util/synthetic-events.c
> @@ -379,7 +379,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> }
> io__init(&io, io.fd, bf, sizeof(bf));
>
> - event->header.type = PERF_RECORD_MMAP2;
> + event->header.type = PERF_RECORD_MMAP3;

This also needs to check if the user is interested in build-id records.
If it is disabled, then using this new tool with mmap3 support will
generate perf.data files that will bot be grokked by older tools,
introducing an annoyance for people not interested in build-ids.

- Arnaldo

> t = rdclock();
>
> while (!io.eof) {
> @@ -387,20 +387,20 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> size_t size;
>
> /* ensure null termination since stack will be reused. */
> - event->mmap2.filename[0] = '\0';
> + event->mmap3.filename[0] = '\0';
>
> /* 00400000-0040c000 r-xp 00000000 fd:01 41038 /bin/cat */
> if (!read_proc_maps_line(&io,
> - &event->mmap2.start,
> - &event->mmap2.len,
> - &event->mmap2.prot,
> - &event->mmap2.flags,
> - &event->mmap2.pgoff,
> - &event->mmap2.maj,
> - &event->mmap2.min,
> - &event->mmap2.ino,
> - sizeof(event->mmap2.filename),
> - event->mmap2.filename))
> + &event->mmap3.start,
> + &event->mmap3.len,
> + &event->mmap3.prot,
> + &event->mmap3.flags,
> + &event->mmap3.pgoff,
> + &event->mmap3.maj,
> + &event->mmap3.min,
> + &event->mmap3.ino,
> + sizeof(event->mmap3.filename),
> + event->mmap3.filename))
> continue;
>
> if ((rdclock() - t) > timeout) {
> @@ -412,7 +412,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> goto out;
> }
>
> - event->mmap2.ino_generation = 0;
> + event->mmap3.ino_generation = 0;
>
> /*
> * Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
> @@ -422,8 +422,8 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> else
> event->header.misc = PERF_RECORD_MISC_GUEST_USER;
>
> - if ((event->mmap2.prot & PROT_EXEC) == 0) {
> - if (!mmap_data || (event->mmap2.prot & PROT_READ) == 0)
> + if ((event->mmap3.prot & PROT_EXEC) == 0) {
> + if (!mmap_data || (event->mmap3.prot & PROT_READ) == 0)
> continue;
>
> event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
> @@ -433,25 +433,37 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> if (truncation)
> event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT;
>
> - if (!strcmp(event->mmap2.filename, ""))
> - strcpy(event->mmap2.filename, anonstr);
> + if (!strcmp(event->mmap3.filename, ""))
> + strcpy(event->mmap3.filename, anonstr);
>
> if (hugetlbfs_mnt_len &&
> - !strncmp(event->mmap2.filename, hugetlbfs_mnt,
> + !strncmp(event->mmap3.filename, hugetlbfs_mnt,
> hugetlbfs_mnt_len)) {
> - strcpy(event->mmap2.filename, anonstr);
> - event->mmap2.flags |= MAP_HUGETLB;
> + strcpy(event->mmap3.filename, anonstr);
> + event->mmap3.flags |= MAP_HUGETLB;
> }
>
> - size = strlen(event->mmap2.filename) + 1;
> + size = strlen(event->mmap3.filename) + 1;
> size = PERF_ALIGN(size, sizeof(u64));
> - event->mmap2.len -= event->mmap.start;
> - event->mmap2.header.size = (sizeof(event->mmap2) -
> - (sizeof(event->mmap2.filename) - size));
> - memset(event->mmap2.filename + size, 0, machine->id_hdr_size);
> - event->mmap2.header.size += machine->id_hdr_size;
> - event->mmap2.pid = tgid;
> - event->mmap2.tid = pid;
> + event->mmap3.len -= event->mmap.start;
> + event->mmap3.header.size = (sizeof(event->mmap3) -
> + (sizeof(event->mmap3.filename) - size));
> + memset(event->mmap3.filename + size, 0, machine->id_hdr_size);
> + event->mmap3.header.size += machine->id_hdr_size;
> + event->mmap3.pid = tgid;
> + event->mmap3.tid = pid;
> +
> + rc = filename__read_build_id(event->mmap3.filename, event->mmap3.buildid,
> + BUILD_ID_SIZE);
> + if (rc != BUILD_ID_SIZE) {
> + if (event->mmap3.filename[0] == '/') {
> + pr_debug2("Failed to read build ID for %s\n",
> + event->mmap3.filename);
> + }
> + memset(event->mmap3.buildid, 0x0, sizeof(event->mmap3.buildid));
> + }
> +
> + rc = 0;
>
> if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
> rc = -1;
> @@ -744,7 +756,7 @@ int perf_event__synthesize_thread_map(struct perf_tool *tool,
> if (comm_event == NULL)
> goto out;
>
> - mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
> + mmap_event = malloc(sizeof(mmap_event->mmap3) + machine->id_hdr_size);
> if (mmap_event == NULL)
> goto out_free_comm;
>
> @@ -826,7 +838,7 @@ static int __perf_event__synthesize_threads(struct perf_tool *tool,
> if (comm_event == NULL)
> goto out;
>
> - mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
> + mmap_event = malloc(sizeof(mmap_event->mmap3) + machine->id_hdr_size);
> if (mmap_event == NULL)
> goto out_free_comm;
>
> --
> 2.26.2
>

--

- Arnaldo