Before this patch, when using overwritable ring buffer on an old
kernel, error message is misleading:
# ~/perf record -m 1 -e raw_syscalls:*/overwrite/ -a
Error:
The raw_syscalls:sys_enter event is not supported.
This patch output clear error message to tell user his/her kernel
is too old:
# ~/perf record -m 1 -e raw_syscalls:*/overwrite/ -a
Reading from overwrite event is not supported by this kernel
Error:
The raw_syscalls:sys_enter event is not supported.
Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
tools/perf/util/evsel.c | 17 +++++------------
tools/perf/util/evsel.h | 13 +++++++++++++
tools/perf/util/record.c | 17 +++++++++++++++++
3 files changed, 35 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ef223c7..59a69bb 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -29,17 +29,7 @@
#include "trace-event.h"
#include "stat.h"
-static struct {
- bool sample_id_all;
- bool exclude_guest;
- bool mmap2;
- bool cloexec;
- bool clockid;
- bool clockid_wrong;
- bool lbr_flags;
- bool write_backward;
-} perf_missing_features;
-
+struct perf_missing_features perf_missing_features;
static clockid_t clockid;
static int perf_evsel__no_extra_init(struct perf_evsel *evsel __maybe_unused)
@@ -690,8 +680,11 @@ static void apply_config_terms(struct perf_evsel *evsel,
* possible to set overwrite globally, without config
* terms.
*/
- if (evsel->overwrite)
+ if (evsel->overwrite) {
+ WARN_ONCE(perf_missing_features.write_backward,
+ "Reading from overwrite event is not supported by
this kernel\n");
attr->write_backward = 1;
+ }
/* User explicitly set per-event callgraph, clear the old setting and
reset. */
if ((callgraph_buf != NULL) || (dump_size > 0) || max_stack) {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 55ff958..17e506a 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -11,6 +11,19 @@
#include "cpumap.h"
#include "counts.h"
+struct perf_missing_features {
+ bool sample_id_all;
+ bool exclude_guest;
+ bool mmap2;
+ bool cloexec;
+ bool clockid;
+ bool clockid_wrong;
+ bool lbr_flags;
+ bool write_backward;
+};
+
+extern struct perf_missing_features perf_missing_features;
+
struct perf_evsel;
/*
diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
index 481792c..e3ab812 100644
--- a/tools/perf/util/record.c
+++ b/tools/perf/util/record.c
@@ -90,6 +90,11 @@ static void perf_probe_context_switch(struct perf_evsel
*evsel)
evsel->attr.context_switch = 1;
}
+static void perf_probe_write_backward(struct perf_evsel *evsel)
+{
+ evsel->attr.write_backward = 1;
+}
+
bool perf_can_sample_identifier(void)
{
return perf_probe_api(perf_probe_sample_identifier);
@@ -129,6 +134,17 @@ bool perf_can_record_cpu_wide(void)
return true;
}
+static void perf_check_write_backward(void)
+{
+ static bool checked = false;
+
+ if (!checked) {
+ perf_missing_features.write_backward =
+ !perf_probe_api(perf_probe_write_backward);
+ checked = true;
+ }
+}
+
void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
struct callchain_param *callchain)
{
@@ -136,6 +152,7 @@ void perf_evlist__config(struct perf_evlist *evlist, struct
record_opts *opts,
bool use_sample_identifier = false;
bool use_comm_exec;
+ perf_check_write_backward();
/*
* Set the evsel leader links before we configure attributes,
* since some might depend on this info.
--
1.8.3.4
