[PATCH V2 04/22] perf tools: Add support for Instruction Trace recording

Adrian Hunter
2014-11-20T13:25:36Z

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 | 195 +++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/itrace.h | 59 +++++++++++++-
tools/perf/util/record.c | 11 ++-
4 files changed, 265 insertions(+), 2 deletions(-)

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 1dabb85..ca4c09d 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -53,8 +53,10 @@ struct record_opts {
bool sample_time;
bool period;
bool sample_intr_regs;
+ 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 c950b4f..08372a9 100644
--- a/tools/perf/util/itrace.c
+++ b/tools/perf/util/itrace.c
@@ -21,6 +21,10 @@
#include <linux/perf_event.h>
#include <linux/types.h>

+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
#include "../perf.h"
#include "util.h"
#include "evlist.h"
@@ -28,6 +32,9 @@
#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)
{
@@ -97,3 +104,191 @@ 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(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..44b6a01 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(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 cf69325..656eaa3 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