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Message-ID: <20240927185340.658143-8-howardchu95@gmail.com>
Date: Fri, 27 Sep 2024 11:53:39 -0700
From: Howard Chu <howardchu95@...il.com>
To: peterz@...radead.org
Cc: mingo@...hat.com,
acme@...nel.org,
namhyung@...nel.org,
mark.rutland@....com,
alexander.shishkin@...ux.intel.com,
jolsa@...nel.org,
irogers@...gle.com,
adrian.hunter@...el.com,
kan.liang@...ux.intel.com,
linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org,
Howard Chu <howardchu95@...il.com>
Subject: [PATCH v5 7/8] perf record --off-cpu: Parse BPF output embedded data
Move evsel__is_offcpu_event() to evsel.h
Add a sample_type_embed member to the struct evsel, along with a couple
of helper functions.
In session.c, we parse BPF output embedded samples in a two-step
process.
Initial Parsing: Treat the sample as a regular BPF-output event.
Secondary Parsing: Extract data from raw_data and parse it according to
the sample_type_embed specification. Since the second step relies on the
raw_data obtained in the first step, we must avoid zero-initializing the
sample data after the first step.
Suggested-by: Ian Rogers <irogers@...gle.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@...nel.org>
Signed-off-by: Howard Chu <howardchu95@...il.com>
---
tools/perf/builtin-script.c | 4 ++--
tools/perf/util/evsel.c | 39 +++++++++++++++++++++++--------------
tools/perf/util/evsel.h | 6 ++++++
tools/perf/util/session.c | 12 +++++++++++-
4 files changed, 43 insertions(+), 18 deletions(-)
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index a644787fa9e1..9719ffae45d5 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -662,7 +662,7 @@ static int perf_session__check_output_opt(struct perf_session *session)
evlist__for_each_entry(session->evlist, evsel) {
not_pipe = true;
- if (evsel__has_callchain(evsel)) {
+ if (evsel__has_callchain(evsel) || evsel__is_offcpu_event(evsel)) {
use_callchain = true;
break;
}
@@ -2352,7 +2352,7 @@ static void process_event(struct perf_script *script,
else if (PRINT_FIELD(BRSTACKOFF))
perf_sample__fprintf_brstackoff(sample, thread, attr, fp);
- if (evsel__is_bpf_output(evsel) && PRINT_FIELD(BPF_OUTPUT))
+ if (evsel__is_bpf_output(evsel) && !evsel__is_offcpu_event(evsel) && PRINT_FIELD(BPF_OUTPUT))
perf_sample__fprintf_bpf_output(sample, fp);
perf_sample__fprintf_insn(sample, evsel, attr, thread, machine, fp, al);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 32196e4f0637..4199a1e409f7 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1105,11 +1105,6 @@ static void evsel__set_default_freq_period(struct record_opts *opts,
}
}
-static bool evsel__is_offcpu_event(struct evsel *evsel)
-{
- return evsel__is_bpf_output(evsel) && evsel__name_is(evsel, OFFCPU_EVENT);
-}
-
/*
* The enable_on_exec/disabled value strategy:
*
@@ -2677,6 +2672,7 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
u16 max_size = event->header.size;
const void *endp = (void *)event + max_size;
u64 sz;
+ bool ip_in_callchain = false;
/*
* used for cross-endian analysis. See git commit 65014ab3
@@ -2684,14 +2680,25 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
*/
union u64_swap u;
- memset(data, 0, sizeof(*data));
- data->cpu = data->pid = data->tid = -1;
- data->stream_id = data->id = data->time = -1ULL;
- data->period = evsel->core.attr.sample_period;
- data->cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
- data->misc = event->header.misc;
- data->data_src = PERF_MEM_DATA_SRC_NONE;
- data->vcpu = -1;
+ /*
+ * For sample data embedded in BPF output, don't clear the sample we read in the first pass,
+ * and read the embedded data from raw_data in the second pass.
+ */
+ if (evsel__is_offcpu_event(evsel) && data->raw_data) {
+ type = OFFCPU_EMBEDDED_SAMPLE_TYPES;
+ array = data->raw_data;
+ ip_in_callchain = true;
+ } else { /* for normal samples, clear to zero before reading */
+ array = event->sample.array;
+ memset(data, 0, sizeof(*data));
+ data->cpu = data->pid = data->tid = -1;
+ data->stream_id = data->id = data->time = -1ULL;
+ data->period = evsel->core.attr.sample_period;
+ data->cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+ data->misc = event->header.misc;
+ data->data_src = PERF_MEM_DATA_SRC_NONE;
+ data->vcpu = -1;
+ }
if (event->header.type != PERF_RECORD_SAMPLE) {
if (!evsel->core.attr.sample_id_all)
@@ -2699,8 +2706,6 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
return perf_evsel__parse_id_sample(evsel, event, data);
}
- array = event->sample.array;
-
if (perf_event__check_size(event, evsel->sample_size))
return -EFAULT;
@@ -2822,6 +2827,10 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
data->callchain = (struct ip_callchain *)array++;
if (data->callchain->nr > max_callchain_nr)
return -EFAULT;
+
+ if (ip_in_callchain && data->callchain->nr > 1)
+ data->ip = data->callchain->ips[1];
+
sz = data->callchain->nr * sizeof(u64);
OVERFLOW_CHECK(array, sz, max_size);
array = (void *)array + sz;
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 3e751ea769ac..6fbf5d4219d1 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -11,6 +11,7 @@
#include <perf/evsel.h>
#include "symbol_conf.h"
#include "pmus.h"
+#include "off_cpu.h"
struct bpf_object;
struct cgroup;
@@ -580,4 +581,9 @@ u64 evsel__bitfield_swap_branch_flags(u64 value);
void evsel__set_config_if_unset(struct perf_pmu *pmu, struct evsel *evsel,
const char *config_name, u64 val);
+static inline bool evsel__is_offcpu_event(struct evsel *evsel)
+{
+ return evsel__is_bpf_output(evsel) && evsel__name_is(evsel, OFFCPU_EVENT);
+}
+
#endif /* __PERF_EVSEL_H */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index dbaf07bf6c5f..d481bc466131 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1229,6 +1229,16 @@ static int evlist__deliver_sample(struct evlist *evlist, const struct perf_tool
u64 sample_type = evsel->core.attr.sample_type;
u64 read_format = evsel->core.attr.read_format;
+ /* parse sample the second time to get embedded data from raw_data */
+ if (evsel__is_offcpu_event(evsel) && sample->raw_data) {
+ int err = evsel__parse_sample(evsel, event, sample);
+
+ if (err) {
+ pr_err("Failed to parse BPF ouput embedded data, err = %d\n", err);
+ return err;
+ }
+ }
+
/* Standard sample delivery. */
if (!(sample_type & PERF_SAMPLE_READ))
return tool->sample(tool, event, sample, evsel, machine);
@@ -1339,7 +1349,7 @@ static int perf_session__deliver_event(struct perf_session *session,
u64 file_offset,
const char *file_path)
{
- struct perf_sample sample;
+ struct perf_sample sample = { .raw_data = NULL }; /* avoid accidental read of embedded data */
int ret = evlist__parse_sample(session->evlist, event, &sample);
if (ret) {
--
2.43.0
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