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Commit b90dc17a authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf evsel: Add overwrite attribute and check write_backward 



Add 'overwrite' attribute to evsel to mark whether this event is
overwritable. The following commits will support syntax like:

  # perf record -e cycles/overwrite/ ...

An overwritable evsel requires kernel support for the
perf_event_attr.write_backward ring buffer feature.

Add it to perf_missing_feature.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1463762315-155689-2-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 408cf677

tools/perf/util/evsel.c

+13 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ static struct { 
	bool clockid;

	bool clockid_wrong;

	bool lbr_flags;

	bool write_backward;

} perf_missing_features;



static clockid_t clockid;
@@ -1376,6 +1377,8 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, 
	if (perf_missing_features.lbr_flags)

		evsel->attr.branch_sample_type &= ~(PERF_SAMPLE_BRANCH_NO_FLAGS |

				     PERF_SAMPLE_BRANCH_NO_CYCLES);

	if (perf_missing_features.write_backward)

		evsel->attr.write_backward = false;

retry_sample_id:

	if (perf_missing_features.sample_id_all)

		evsel->attr.sample_id_all = 0;
@@ -1438,6 +1441,12 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, 
				err = -EINVAL;

				goto out_close;

			}



			if (evsel->overwrite &&

			    perf_missing_features.write_backward) {

				err = -EINVAL;

				goto out_close;

			}

		}

	}
@@ -1500,6 +1509,10 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus, 
			  PERF_SAMPLE_BRANCH_NO_FLAGS))) {

		perf_missing_features.lbr_flags = true;

		goto fallback_missing_features;

	} else if (!perf_missing_features.write_backward &&

			evsel->attr.write_backward) {

		perf_missing_features.write_backward = true;

		goto fallback_missing_features;

	}



out_close:

tools/perf/util/evsel.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ struct perf_evsel { 
	bool			tracking;

	bool			per_pkg;

	bool			precise_max;

	bool			overwrite;

	/* parse modifier helper */

	int			exclude_GH;

	int			nr_members;