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Subject[PATCH V5 04/25] perf tools: Add support for Instruction Trace recording
Date
Add support for reading from the Instruction
Tracing mmap and synthesizing Instruction
Tracing events.

This patch introduces an abstraction for recording
Instruction Trace data. Recording is initialized
by itrace_record__init() which is a weak function
to be implemented by the architecture to provide
recording callbacks. Recording is mainly handled
by itrace_mmap__read() and
perf_event__synthesize_itrace() but there are
callbacks for miscellaneous needs including
validating and processing user options, populating
private data in itrace_info_event, and freeing
the structure when finished.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/perf.h | 2 +
tools/perf/util/itrace.c | 196 +++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/itrace.h | 59 +++++++++++++-
tools/perf/util/record.c | 11 ++-
4 files changed, 266 insertions(+), 2 deletions(-)

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 1caa70a..8b39c1b 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_itrace;
unsigned int freq;
unsigned int mmap_pages;
+ unsigned int itrace_mmap_pages;
unsigned int user_freq;
u64 branch_stack;
u64 default_interval;
diff --git a/tools/perf/util/itrace.c b/tools/perf/util/itrace.c
index 021f49f..d8fc89d 100644
--- a/tools/perf/util/itrace.c
+++ b/tools/perf/util/itrace.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"
@@ -30,6 +34,9 @@
#include "thread_map.h"
#include "itrace.h"

+#include "event.h"
+#include "debug.h"
+
int itrace_mmap__mmap(struct itrace_mmap *mm, struct itrace_mmap_params *mp,
void *userpg, int fd)
{
@@ -99,3 +106,192 @@ void itrace_mmap_params__set_idx(struct itrace_mmap_params *mp,
mp->tid = evlist->threads->map[idx];
}
}
+
+size_t itrace_record__info_priv_size(struct itrace_record *itr)
+{
+ if (itr)
+ return itr->info_priv_size(itr);
+ return 0;
+}
+
+static int itrace_not_supported(void)
+{
+ pr_err("Instruction tracing is not supported on this architecture\n");
+ return -EINVAL;
+}
+
+int itrace_record__info_fill(struct itrace_record *itr,
+ struct perf_session *session,
+ struct itrace_info_event *itrace_info,
+ size_t priv_size)
+{
+ if (itr)
+ return itr->info_fill(itr, session, itrace_info, priv_size);
+ return itrace_not_supported();
+}
+
+void itrace_record__free(struct itrace_record *itr)
+{
+ if (itr)
+ itr->free(itr);
+}
+
+int itrace_record__options(struct itrace_record *itr,
+ struct perf_evlist *evlist,
+ struct record_opts *opts)
+{
+ if (itr)
+ return itr->recording_options(itr, evlist, opts);
+ return 0;
+}
+
+u64 itrace_record__reference(struct itrace_record *itr)
+{
+ if (itr)
+ return itr->reference(itr);
+ return 0;
+}
+
+struct itrace_record *__weak
+itrace_record__init(struct perf_evlist *evlist __maybe_unused, int *err)
+{
+ *err = 0;
+ return NULL;
+}
+
+int perf_event__synthesize_itrace_info(struct itrace_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 itrace information\n");
+ priv_size = itrace_record__info_priv_size(itr);
+ ev = zalloc(sizeof(struct itrace_info_event) + priv_size);
+ if (!ev)
+ return -ENOMEM;
+
+ ev->itrace_info.header.type = PERF_RECORD_ITRACE_INFO;
+ ev->itrace_info.header.size = sizeof(struct itrace_info_event) +
+ priv_size;
+ err = itrace_record__info_fill(itr, session, &ev->itrace_info,
+ priv_size);
+ if (err)
+ goto out_free;
+
+ err = process(tool, ev, NULL, NULL);
+out_free:
+ free(ev);
+ return err;
+}
+
+int perf_event__synthesize_itrace(struct perf_tool *tool,
+ perf_event__handler_t process,
+ size_t size, u64 offset, u64 ref, int idx,
+ u32 tid, u32 cpu)
+{
+ union perf_event ev;
+
+ memset(&ev, 0, sizeof(ev));
+ ev.itrace.header.type = PERF_RECORD_ITRACE;
+ ev.itrace.header.size = sizeof(ev.itrace);
+ ev.itrace.size = size;
+ ev.itrace.offset = offset;
+ ev.itrace.reference = ref;
+ ev.itrace.idx = idx;
+ ev.itrace.tid = tid;
+ ev.itrace.cpu = cpu;
+
+ return process(tool, &ev, NULL, NULL);
+}
+
+int itrace_mmap__read(struct itrace_mmap *mm, struct itrace_record *itr,
+ struct perf_tool *tool, process_itrace_t fn)
+{
+ u64 head = itrace_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("itrace 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 = itrace_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_itrace() */
+ padding = size & 7;
+ if (padding)
+ padding = 8 - padding;
+
+ memset(&ev, 0, sizeof(ev));
+ ev.itrace.header.type = PERF_RECORD_ITRACE;
+ ev.itrace.header.size = sizeof(ev.itrace);
+ ev.itrace.size = size + padding;
+ ev.itrace.offset = offset;
+ ev.itrace.reference = ref;
+ ev.itrace.idx = mm->idx;
+ ev.itrace.tid = mm->tid;
+ ev.itrace.cpu = mm->cpu;
+
+ if (fn(tool, &ev, data1, len1, data2, len2))
+ return -1;
+
+ mm->prev = head;
+
+ itrace_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/itrace.h b/tools/perf/util/itrace.h
index 00ba409..6eef25c 100644
--- a/tools/perf/util/itrace.h
+++ b/tools/perf/util/itrace.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 itrace_info_event;

/**
* struct itrace_mmap - records an mmap of the itrace buffer.
@@ -70,6 +75,29 @@ struct itrace_mmap_params {
int cpu;
};

+/**
+ * struct itrace_record - callbacks for recording Instruction Trace data.
+ * @recording_options: validate and process recording options
+ * @info_priv_size: return the size of the private data in itrace_info_event
+ * @info_fill: fill-in the private data in itrace_info_event
+ * @free: free this itrace record structure
+ * @reference: provide a 64-bit reference number for itrace_event
+ * @read_finish: called after reading from an itrace mmap
+ */
+struct itrace_record {
+ int (*recording_options)(struct itrace_record *itr,
+ struct perf_evlist *evlist,
+ struct record_opts *opts);
+ size_t (*info_priv_size)(struct itrace_record *itr);
+ int (*info_fill)(struct itrace_record *itr,
+ struct perf_session *session,
+ struct itrace_info_event *itrace_info,
+ size_t priv_size);
+ void (*free)(struct itrace_record *itr);
+ u64 (*reference)(struct itrace_record *itr);
+ int (*read_finish)(struct itrace_record *itr, int idx);
+};
+
static inline u64 itrace_mmap__read_head(struct itrace_mmap *mm __maybe_unused)
{
/* Not yet implemented */
@@ -93,4 +121,33 @@ void itrace_mmap_params__set_idx(struct itrace_mmap_params *mp,
struct perf_evlist *evlist, int idx,
bool per_cpu);

+typedef int (*process_itrace_t)(struct perf_tool *tool, union perf_event *event,
+ void *data1, size_t len1, void *data2,
+ size_t len2);
+
+int itrace_mmap__read(struct itrace_mmap *mm, struct itrace_record *itr,
+ struct perf_tool *tool, process_itrace_t fn);
+
+struct itrace_record *itrace_record__init(struct perf_evlist *evlist, int *err);
+
+int itrace_record__options(struct itrace_record *itr,
+ struct perf_evlist *evlist,
+ struct record_opts *opts);
+size_t itrace_record__info_priv_size(struct itrace_record *itr);
+int itrace_record__info_fill(struct itrace_record *itr,
+ struct perf_session *session,
+ struct itrace_info_event *itrace_info,
+ size_t priv_size);
+void itrace_record__free(struct itrace_record *itr);
+u64 itrace_record__reference(struct itrace_record *itr);
+
+int perf_event__synthesize_itrace_info(struct itrace_record *itr,
+ struct perf_tool *tool,
+ struct perf_session *session,
+ perf_event__handler_t process);
+int perf_event__synthesize_itrace(struct perf_tool *tool,
+ perf_event__handler_t process,
+ size_t size, u64 offset, u64 ref, int idx,
+ u32 tid, u32 cpu);
+
#endif
diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
index 8acd0df..1887484 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_itrace) {
+ /*
+ * 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 = true;
+ 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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