Re: [PATCH 04/44] perf tools: Add support for AUX area recording

From: Arnaldo Carvalho de Melo
Date: Mon Apr 20 2015 - 19:18:05 EST

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Em Thu, Apr 09, 2015 at 06:53:44PM +0300, Adrian Hunter escreveu:
> Add support for reading from the AUX area
> tracing mmap and synthesizing AUX area
> tracing events.
>
> This patch introduces an abstraction for recording
> AUX area data. Recording is initialized
> by auxtrace_record__init() which is a weak function
> to be implemented by the architecture to provide
> recording callbacks. Recording is mainly handled
> by auxtrace_mmap__read() and
> perf_event__synthesize_auxtrace() but there are
> callbacks for miscellaneous needs including
> validating and processing user options, populating
> private data in auxtrace_info_event, and freeing
> the structure when finished.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/perf/perf.h | 2 +
> tools/perf/util/auxtrace.c | 176 +++++++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/auxtrace.h | 56 ++++++++++++++-
> tools/perf/util/record.c | 11 ++-
> 4 files changed, 243 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index e14bb63..5042093 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -54,8 +54,10 @@ struct record_opts {
> bool period;
> bool sample_intr_regs;
> bool running_time;
> + bool full_auxtrace;
> unsigned int freq;
> unsigned int mmap_pages;
> + unsigned int auxtrace_mmap_pages;
> unsigned int user_freq;
> u64 branch_stack;
> u64 default_interval;
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index dedb646..2cafea2 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -23,6 +23,10 @@
> #include <linux/bitops.h>
> #include <linux/log2.h>
>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +
> #include "../perf.h"
> #include "util.h"
> #include "evlist.h"
> @@ -31,6 +35,9 @@
> #include "asm/bug.h"
> #include "auxtrace.h"
>
> +#include "event.h"
> +#include "debug.h"
> +
> int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
> struct auxtrace_mmap_params *mp,
> void *userpg, int fd)
> @@ -111,3 +118,172 @@ void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
> mp->tid = evlist->threads->map[idx];
> }
> }
> +
> +size_t auxtrace_record__info_priv_size(struct auxtrace_record *itr)
> +{
> + if (itr)
> + return itr->info_priv_size(itr);
> + return 0;
> +}

return itr ? itr->info_priv_size(itr) : 0;

Is more compact, applying anyway... There is one other comment below,
but it is as well cosmetic.

- Arnaldo

> +
> +static int auxtrace_not_supported(void)
> +{
> + pr_err("AUX area tracing is not supported on this architecture\n");
> + return -EINVAL;
> +}
> +
> +int auxtrace_record__info_fill(struct auxtrace_record *itr,
> + struct perf_session *session,
> + struct auxtrace_info_event *auxtrace_info,
> + size_t priv_size)
> +{
> + if (itr)
> + return itr->info_fill(itr, session, auxtrace_info, priv_size);
> + return auxtrace_not_supported();
> +}
> +
> +void auxtrace_record__free(struct auxtrace_record *itr)
> +{
> + if (itr)
> + itr->free(itr);
> +}
> +
> +int auxtrace_record__options(struct auxtrace_record *itr,
> + struct perf_evlist *evlist,
> + struct record_opts *opts)
> +{
> + if (itr)
> + return itr->recording_options(itr, evlist, opts);
> + return 0;
> +}
> +
> +u64 auxtrace_record__reference(struct auxtrace_record *itr)
> +{
> + if (itr)
> + return itr->reference(itr);
> + return 0;
> +}
> +
> +struct auxtrace_record *__weak
> +auxtrace_record__init(struct perf_evlist *evlist __maybe_unused, int *err)
> +{
> + *err = 0;
> + return NULL;
> +}
> +
> +int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr,
> + struct perf_tool *tool,
> + struct perf_session *session,
> + perf_event__handler_t process)
> +{
> + union perf_event *ev;
> + size_t priv_size;
> + int err;
> +
> + pr_debug2("Synthesizing auxtrace information\n");
> + priv_size = auxtrace_record__info_priv_size(itr);
> + ev = zalloc(sizeof(struct auxtrace_info_event) + priv_size);
> + if (!ev)
> + return -ENOMEM;
> +
> + ev->auxtrace_info.header.type = PERF_RECORD_AUXTRACE_INFO;
> + ev->auxtrace_info.header.size = sizeof(struct auxtrace_info_event) +
> + priv_size;
> + err = auxtrace_record__info_fill(itr, session, &ev->auxtrace_info,
> + priv_size);
> + if (err)
> + goto out_free;
> +
> + err = process(tool, ev, NULL, NULL);
> +out_free:

if (!err)
err = process(tool, ev, NULL, NULL);

> + free(ev);
> + return err;

I.e. I love gotos, but this one isn't needed :-)

> +}
> +
> +int auxtrace_mmap__read(struct auxtrace_mmap *mm, struct auxtrace_record *itr,
> + struct perf_tool *tool, process_auxtrace_t fn)
> +{
> + u64 head = auxtrace_mmap__read_head(mm);
> + u64 old = mm->prev, offset, ref;
> + unsigned char *data = mm->base;
> + size_t size, head_off, old_off, len1, len2, padding;
> + union perf_event ev;
> + void *data1, *data2;
> +
> + if (old == head)
> + return 0;
> +
> + pr_debug3("auxtrace idx %d old %#"PRIx64" head %#"PRIx64" diff %#"PRIx64"\n",
> + mm->idx, old, head, head - old);
> +
> + if (mm->mask) {
> + head_off = head & mm->mask;
> + old_off = old & mm->mask;
> + } else {
> + head_off = head % mm->len;
> + old_off = old % mm->len;
> + }
> +
> + if (head_off > old_off)
> + size = head_off - old_off;
> + else
> + size = mm->len - (old_off - head_off);
> +
> + ref = auxtrace_record__reference(itr);
> +
> + if (head > old || size <= head || mm->mask) {
> + offset = head - size;
> + } else {
> + /*
> + * When the buffer size is not a power of 2, 'head' wraps at the
> + * highest multiple of the buffer size, so we have to subtract
> + * the remainder here.
> + */
> + u64 rem = (0ULL - mm->len) % mm->len;
> +
> + offset = head - size - rem;
> + }
> +
> + if (size > head_off) {
> + len1 = size - head_off;
> + data1 = &data[mm->len - len1];
> + len2 = head_off;
> + data2 = &data[0];
> + } else {
> + len1 = size;
> + data1 = &data[head_off - len1];
> + len2 = 0;
> + data2 = NULL;
> + }
> +
> + /* padding must be written by fn() e.g. record__process_auxtrace() */
> + padding = size & 7;
> + if (padding)
> + padding = 8 - padding;
> +
> + memset(&ev, 0, sizeof(ev));
> + ev.auxtrace.header.type = PERF_RECORD_AUXTRACE;
> + ev.auxtrace.header.size = sizeof(ev.auxtrace);
> + ev.auxtrace.size = size + padding;
> + ev.auxtrace.offset = offset;
> + ev.auxtrace.reference = ref;
> + ev.auxtrace.idx = mm->idx;
> + ev.auxtrace.tid = mm->tid;
> + ev.auxtrace.cpu = mm->cpu;
> +
> + if (fn(tool, &ev, data1, len1, data2, len2))
> + return -1;
> +
> + mm->prev = head;
> +
> + auxtrace_mmap__write_tail(mm, head);
> + if (itr->read_finish) {
> + int err;
> +
> + err = itr->read_finish(itr, mm->idx);
> + if (err < 0)
> + return err;
> + }
> +
> + return 1;
> +}
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 2071b36..7ab4850 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -18,13 +18,18 @@
>
> #include <sys/types.h>
> #include <stdbool.h>
> -
> +#include <stddef.h>
> #include <linux/perf_event.h>
> #include <linux/types.h>
>
> #include "../perf.h"
>
> +union perf_event;
> +struct perf_session;
> struct perf_evlist;
> +struct perf_tool;
> +struct record_opts;
> +struct auxtrace_info_event;
>
> /**
> * struct auxtrace_mmap - records an mmap of the auxtrace buffer.
> @@ -70,6 +75,29 @@ struct auxtrace_mmap_params {
> int cpu;
> };
>
> +/**
> + * struct auxtrace_record - callbacks for recording AUX area data.
> + * @recording_options: validate and process recording options
> + * @info_priv_size: return the size of the private data in auxtrace_info_event
> + * @info_fill: fill-in the private data in auxtrace_info_event
> + * @free: free this auxtrace record structure
> + * @reference: provide a 64-bit reference number for auxtrace_event
> + * @read_finish: called after reading from an auxtrace mmap
> + */
> +struct auxtrace_record {
> + int (*recording_options)(struct auxtrace_record *itr,
> + struct perf_evlist *evlist,
> + struct record_opts *opts);
> + size_t (*info_priv_size)(struct auxtrace_record *itr);
> + int (*info_fill)(struct auxtrace_record *itr,
> + struct perf_session *session,
> + struct auxtrace_info_event *auxtrace_info,
> + size_t priv_size);
> + void (*free)(struct auxtrace_record *itr);
> + u64 (*reference)(struct auxtrace_record *itr);
> + int (*read_finish)(struct auxtrace_record *itr, int idx);
> +};
> +
> static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
> {
> struct perf_event_mmap_page *pc = mm->userpg;
> @@ -114,4 +142,30 @@ void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
> struct perf_evlist *evlist, int idx,
> bool per_cpu);
>
> +typedef int (*process_auxtrace_t)(struct perf_tool *tool,
> + union perf_event *event, void *data1,
> + size_t len1, void *data2, size_t len2);
> +
> +int auxtrace_mmap__read(struct auxtrace_mmap *mm, struct auxtrace_record *itr,
> + struct perf_tool *tool, process_auxtrace_t fn);
> +
> +struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,
> + int *err);
> +
> +int auxtrace_record__options(struct auxtrace_record *itr,
> + struct perf_evlist *evlist,
> + struct record_opts *opts);
> +size_t auxtrace_record__info_priv_size(struct auxtrace_record *itr);
> +int auxtrace_record__info_fill(struct auxtrace_record *itr,
> + struct perf_session *session,
> + struct auxtrace_info_event *auxtrace_info,
> + size_t priv_size);
> +void auxtrace_record__free(struct auxtrace_record *itr);
> +u64 auxtrace_record__reference(struct auxtrace_record *itr);
> +
> +int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr,
> + struct perf_tool *tool,
> + struct perf_session *session,
> + perf_event__handler_t process);
> +
> #endif
> diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
> index 8acd0df..0ccfa49 100644
> --- a/tools/perf/util/record.c
> +++ b/tools/perf/util/record.c
> @@ -119,7 +119,16 @@ void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts)
> evsel->attr.comm_exec = 1;
> }
>
> - if (evlist->nr_entries > 1) {
> + if (opts->full_auxtrace) {
> + /*
> + * Need to be able to synthesize and parse selected events with
> + * arbitrary sample types, which requires always being able to
> + * match the id.
> + */
> + use_sample_identifier = perf_can_sample_identifier();
> + evlist__for_each(evlist, evsel)
> + perf_evsel__set_sample_id(evsel, use_sample_identifier);
> + } else if (evlist->nr_entries > 1) {
> struct perf_evsel *first = perf_evlist__first(evlist);
>
> evlist__for_each(evlist, evsel) {
> --
> 1.9.1
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