Alexander Shishkin <alexander.shish...@linux.intel.com> writes:
> With the vmm_exclusive=0, PT seems to be much more usable on BDW now. This
> patchset does three things:
> * adds a flag to PERF_RECORD_AUX, signalling that a transaction has gaps
> in it (due to VMX root mode kicking in),
Hi Arnaldo & Adrian,
In the above context, will something like this be fine?
Regards,
--
Alex
>From 5aba03e79c1119408b44435af8c4cee2480b0775 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin <alexander.shish...@linux.intel.com>
Date: Mon, 20 Feb 2017 17:08:53 +0200
Subject: [PATCH] perf tools: Handle partial AUX records and print a warning
This patch decodes the 'partial' flag in AUX records and prints
a warning to the user, so that they don't have to guess why their
PT traces contain gaps (or missing altogether):
> Warning:
> AUX data had gaps in it 6 times out of 8!
>
> Are you running a KVM guest in the background?
Currently this is the only reason for partial records.
Cc: Adrian Hunter <adrian.hun...@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shish...@linux.intel.com>
---
tools/include/uapi/linux/perf_event.h | 1 +
tools/perf/util/event.c | 5 +++--
tools/perf/util/event.h | 1 +
tools/perf/util/session.c | 17 ++++++++++++++---
4 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/tools/include/uapi/linux/perf_event.h
b/tools/include/uapi/linux/perf_event.h
index c66a485a24..8306415207 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -885,6 +885,7 @@ enum perf_callchain_context {
*/
#define PERF_AUX_FLAG_TRUNCATED 0x01 /* record was truncated
to fit */
#define PERF_AUX_FLAG_OVERWRITE 0x02 /* snapshot from
overwrite mode */
+#define PERF_AUX_FLAG_PARTIAL 0x04 /* record contains gaps */
#define PERF_FLAG_FD_NO_GROUP (1UL << 0)
#define PERF_FLAG_FD_OUTPUT (1UL << 1)
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 4ea7ce72ed..ba193cd019 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -1153,11 +1153,12 @@ int perf_event__process_exit(struct perf_tool *tool
__maybe_unused,
size_t perf_event__fprintf_aux(union perf_event *event, FILE *fp)
{
- return fprintf(fp, " offset: %#"PRIx64" size: %#"PRIx64" flags:
%#"PRIx64" [%s%s]\n",
+ return fprintf(fp, " offset: %#"PRIx64" size: %#"PRIx64" flags:
%#"PRIx64" [%s%s%s]\n",
event->aux.aux_offset, event->aux.aux_size,
event->aux.flags,
event->aux.flags & PERF_AUX_FLAG_TRUNCATED ? "T" : "",
- event->aux.flags & PERF_AUX_FLAG_OVERWRITE ? "O" : "");
+ event->aux.flags & PERF_AUX_FLAG_OVERWRITE ? "O" : "",
+ event->aux.flags & PERF_AUX_FLAG_PARTIAL ? "P" : "");
}
size_t perf_event__fprintf_itrace_start(union perf_event *event, FILE *fp)
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index c735c53a26..d7e53fe176 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -269,6 +269,7 @@ struct events_stats {
u64 total_lost;
u64 total_lost_samples;
u64 total_aux_lost;
+ u64 total_aux_partial;
u64 total_invalid_chains;
u32 nr_events[PERF_RECORD_HEADER_MAX];
u32 nr_non_filtered_samples;
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 4cdbc8f5f1..abdb797fa4 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1258,9 +1258,12 @@ static int machines__deliver_event(struct machines
*machines,
case PERF_RECORD_UNTHROTTLE:
return tool->unthrottle(tool, event, sample, machine);
case PERF_RECORD_AUX:
- if (tool->aux == perf_event__process_aux &&
- (event->aux.flags & PERF_AUX_FLAG_TRUNCATED))
- evlist->stats.total_aux_lost += 1;
+ if (tool->aux == perf_event__process_aux) {
+ if (event->aux.flags & PERF_AUX_FLAG_TRUNCATED)
+ evlist->stats.total_aux_lost += 1;
+ if (event->aux.flags & PERF_AUX_FLAG_PARTIAL)
+ evlist->stats.total_aux_partial += 1;
+ }
return tool->aux(tool, event, sample, machine);
case PERF_RECORD_ITRACE_START:
return tool->itrace_start(tool, event, sample, machine);
@@ -1548,6 +1551,14 @@ static void perf_session__warn_about_errors(const struct
perf_session *session)
stats->nr_events[PERF_RECORD_AUX]);
}
+ if (session->tool->aux == perf_event__process_aux &&
+ stats->total_aux_partial != 0) {
+ ui__warning("AUX data had gaps in it %" PRIu64 " times out of
%u!\n\n"
+ "Are you running a KVM guest in the
background?\n\n",
+ stats->total_aux_partial,
+ stats->nr_events[PERF_RECORD_AUX]);
+ }
+
if (stats->nr_unknown_events != 0) {
ui__warning("Found %u unknown events!\n\n"
"Is this an older tool processing a perf.data "
--
2.11.0
