From: Namhyung Kim <namhy...@kernel.org>
And add the missing feature detection logic to clear the flag on old
kernels.
$ perf record -g -vv true
...
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
size 136
config 0 (PERF_COUNT_HW_CPU_CYCLES)
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|CALLCHAIN|PERIOD
read_format ID|LOST
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
sample_id_all 1
mmap2 1
comm_exec 1
ksymbol 1
bpf_event 1
defer_callchain 1
------------------------------------------------------------
sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off deferred callchain support
Signed-off-by: Namhyung Kim <namhy...@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
tools/perf/util/evsel.c | 24 ++++++++++++++++++++++++
tools/perf/util/evsel.h | 1 +
2 files changed, 25 insertions(+)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6176c31b57ea..c942983b870e 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1076,6 +1076,14 @@ static void __evsel__config_callchain(struct evsel
*evsel, struct record_opts *o
}
}
+ if (param->record_mode == CALLCHAIN_FP &&
!attr->exclude_callchain_user) {
+ /*
+ * Enable deferred callchains optimistically. It'll be switched
+ * off later if the kernel doesn't support it.
+ */
+ attr->defer_callchain = 1;
+ }
+
if (function) {
pr_info("Disabling user space callchains for function trace
event.\n");
attr->exclude_callchain_user = 1;
@@ -2124,6 +2132,8 @@ static int __evsel__prepare_open(struct evsel *evsel,
struct perf_cpu_map *cpus,
static void evsel__disable_missing_features(struct evsel *evsel)
{
+ if (perf_missing_features.defer_callchain)
+ evsel->core.attr.defer_callchain = 0;
if (perf_missing_features.inherit_sample_read &&
evsel->core.attr.inherit &&
(evsel->core.attr.sample_type & PERF_SAMPLE_READ))
evsel->core.attr.inherit = 0;
@@ -2398,6 +2408,15 @@ static bool evsel__detect_missing_features(struct evsel
*evsel, struct perf_cpu
/* Please add new feature detection here. */
+ attr.defer_callchain = true;
+ attr.sample_type = PERF_SAMPLE_CALLCHAIN;
+ if (has_attr_feature(&attr, /*flags=*/0))
+ goto found;
+ perf_missing_features.defer_callchain = true;
+ pr_debug2("switching off deferred callchain support\n");
+ attr.defer_callchain = false;
+ attr.sample_type = 0;
+
attr.inherit = true;
attr.sample_type = PERF_SAMPLE_READ;
if (has_attr_feature(&attr, /*flags=*/0))
@@ -2509,6 +2528,11 @@ static bool evsel__detect_missing_features(struct evsel
*evsel, struct perf_cpu
errno = old_errno;
check:
+ if (evsel->core.attr.defer_callchain &&
+ evsel->core.attr.sample_type & PERF_SAMPLE_CALLCHAIN &&
+ perf_missing_features.defer_callchain)
+ return true;
+
if (evsel->core.attr.inherit &&
(evsel->core.attr.sample_type & PERF_SAMPLE_READ) &&
perf_missing_features.inherit_sample_read)
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 6dbc9690e0c9..a01c1de8f95f 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -221,6 +221,7 @@ struct perf_missing_features {
bool branch_counters;
bool aux_action;
bool inherit_sample_read;
+ bool defer_callchain;
};
extern struct perf_missing_features perf_missing_features;
--
2.47.2
