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perf jit: Let convert_timestamp() to be backwards-compatible

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Commit d110162cafc80dad ("perf tsc: Support cap_user_time_short for
event TIME_CONV") supports the extended parameters for event TIME_CONV,
but it broke the backwards compatibility, so any perf data file with old
event format fails to convert timestamp.

This patch introduces a helper event_contains() to check if an event
contains a specific member or not.  For the backwards-compatibility, if
the event size confirms the extended parameters are supported in the
event TIME_CONV, then copies these parameters.

Committer notes:

To make this compiler backwards compatible add this patch:

  -       struct perf_tsc_conversion tc = { 0 };
  +       struct perf_tsc_conversion tc = { .time_shift = 0, };

Fixes: d110162cafc8 ("perf tsc: Support cap_user_time_short for event TIME_CONV")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steve MacLean <Steve.MacLean@Microsoft.com>
Cc: Yonatan Goldschmidt <yonatan.goldschmidt@granulate.io>
Link: https://lore.kernel.org/r/20210428120915.7123-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Leo Yan 2021-04-28 20:09:13 +08:00 committed by Arnaldo Carvalho de Melo
parent e1d380ea8b
commit aa616f5a8a
2 changed files with 22 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/lib/perf/include/perf/event.h
View File

@ -8,6 +8,8 @@
#include <linux/bpf.h>
#include <sys/types.h> /* pid_t */
#define event_contains(obj, mem) ((obj).header.size > offsetof(typeof(obj), mem))
struct perf_record_mmap {
struct perf_event_header header;
__u32 pid, tid;

30
tools/perf/util/jitdump.c
View File

@ -396,21 +396,31 @@ static pid_t jr_entry_tid(struct jit_buf_desc *jd, union jr_entry *jr)
static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
{
struct perf_tsc_conversion tc;
struct perf_tsc_conversion tc = { .time_shift = 0, };
struct perf_record_time_conv *time_conv = &jd->session->time_conv;
if (!jd->use_arch_timestamp)
return timestamp;
tc.time_shift = jd->session->time_conv.time_shift;
tc.time_mult = jd->session->time_conv.time_mult;
tc.time_zero = jd->session->time_conv.time_zero;
tc.time_cycles = jd->session->time_conv.time_cycles;
tc.time_mask = jd->session->time_conv.time_mask;
tc.cap_user_time_zero = jd->session->time_conv.cap_user_time_zero;
tc.cap_user_time_short = jd->session->time_conv.cap_user_time_short;
tc.time_shift = time_conv->time_shift;
tc.time_mult = time_conv->time_mult;
tc.time_zero = time_conv->time_zero;
if (!tc.cap_user_time_zero)
return 0;
/*
* The event TIME_CONV was extended for the fields from "time_cycles"
* when supported cap_user_time_short, for backward compatibility,
* checks the event size and assigns these extended fields if these
* fields are contained in the event.
*/
if (event_contains(*time_conv, time_cycles)) {
tc.time_cycles = time_conv->time_cycles;
tc.time_mask = time_conv->time_mask;
tc.cap_user_time_zero = time_conv->cap_user_time_zero;
tc.cap_user_time_short = time_conv->cap_user_time_short;
if (!tc.cap_user_time_zero)
return 0;
}
return tsc_to_perf_time(timestamp, &tc);
}