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Subject[PATCH 39/43] perf trace: Add --print-sample
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

To help with debugging, like the interrupted out of order issue that
will be dealt with in the next patch in this series, changing the code
to deal with:

raw_syscalls:sys_enter 411967179.269 Timer 9609/9626 [2]
raw_syscalls:sys_enter 411967179.213 file:// Content 9609/9609 [3]
328.038 (18446744073709.496 ms): Timer/9626 futex(uaddr: 0x7fc0d4027044, op: WAIT|PRIV, utime: 0x7fc0b0ffdb50 ) ...
raw_syscalls:sys_exit 411967179.225 file:// Content 9609/9609 [3]
327.982 ( 0.012 ms): file:// Conten/9609 futex(uaddr: 0x7fc0d4027040, op: WAKE|PRIV, val: 1 ) = 1

That long duration is the bug.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-fljqiibjn7wet24jd1ed7abc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-trace.txt | 4 ++++
tools/perf/builtin-trace.c | 24 ++++++++++++++++++++++++
2 files changed, 28 insertions(+)

diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt
index 6909cf1e0eea..33a88e984e66 100644
--- a/tools/perf/Documentation/perf-trace.txt
+++ b/tools/perf/Documentation/perf-trace.txt
@@ -163,6 +163,10 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs.
Implies '--call-graph dwarf' when --call-graph not present on the
command line, on systems where DWARF unwinding was built in.

+--print-sample::
+ Print the PERF_RECORD_SAMPLE PERF_SAMPLE_ info for the
+ raw_syscalls:sys_{enter,exit} tracepoints, for debugging.
+
--proc-map-timeout::
When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
because the file may be huge. A time out is needed in such cases.
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 7dece5e0cdbb..322c2b15e407 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -110,6 +110,7 @@ struct trace {
bool summary;
bool summary_only;
bool show_comm;
+ bool print_sample;
bool show_tool_stats;
bool trace_syscalls;
bool kernel_syscallchains;
@@ -1578,6 +1579,23 @@ static int trace__printf_interrupted_entry(struct trace *trace, struct perf_samp
return printed;
}

+static int trace__fprintf_sample(struct trace *trace, struct perf_evsel *evsel,
+ struct perf_sample *sample, struct thread *thread)
+{
+ int printed = 0;
+
+ if (trace->print_sample) {
+ double ts = (double)sample->time / NSEC_PER_MSEC;
+
+ printed += fprintf(trace->output, "%22s %10.3f %s %d/%d [%d]\n",
+ perf_evsel__name(evsel), ts,
+ thread__comm_str(thread),
+ sample->pid, sample->tid, sample->cpu);
+ }
+
+ return printed;
+}
+
static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
union perf_event *event __maybe_unused,
struct perf_sample *sample)
@@ -1598,6 +1616,8 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
if (ttrace == NULL)
goto out_put;

+ trace__fprintf_sample(trace, evsel, sample, thread);
+
args = perf_evsel__sc_tp_ptr(evsel, args, sample);

if (ttrace->entry_str == NULL) {
@@ -1688,6 +1708,8 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
if (ttrace == NULL)
goto out_put;

+ trace__fprintf_sample(trace, evsel, sample, thread);
+
if (trace->summary)
thread__update_stats(ttrace, id, sample);

@@ -3034,6 +3056,8 @@ int cmd_trace(int argc, const char **argv)
"Set the maximum stack depth when parsing the callchain, "
"anything beyond the specified depth will be ignored. "
"Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)),
+ OPT_BOOLEAN(0, "print-sample", &trace.print_sample,
+ "print the PERF_RECORD_SAMPLE PERF_SAMPLE_ info, for debugging"),
OPT_UINTEGER(0, "proc-map-timeout", &trace.opts.proc_map_timeout,
"per thread proc mmap processing timeout in ms"),
OPT_UINTEGER('D', "delay", &trace.opts.initial_delay,
--
2.14.3
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