lkml.org 
[lkml]   [2021]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 03/12] perf intel-pt: Support Z itrace option for timeless decoding
Date
Correlating virtual machine TSC packets is not supported at present, so
instead support the Z itrace option.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/Documentation/perf-intel-pt.txt | 5 +++++
tools/perf/util/intel-pt.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
index 1dcec73c910c..33df7898c378 100644
--- a/tools/perf/Documentation/perf-intel-pt.txt
+++ b/tools/perf/Documentation/perf-intel-pt.txt
@@ -869,6 +869,7 @@ The letters are:
L synthesize last branch entries on existing event records
s skip initial number of events
q quicker (less detailed) decoding
+ Z prefer to ignore timestamps (so-called "timeless" decoding)

"Instructions" events look like they were recorded by "perf record -e
instructions".
@@ -1062,6 +1063,10 @@ What *will* be decoded with the qq option:

- instruction pointer associated with PSB packets

+The Z option is equivalent to having recorded a trace without TSC
+(i.e. config term tsc=0). It can be useful to avoid timestamp issues when
+decoding a trace of a virtual machine.
+

dump option
~~~~~~~~~~~
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index eef8970d98fe..7bee969eb335 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -899,7 +899,7 @@ static bool intel_pt_timeless_decoding(struct intel_pt *pt)
bool timeless_decoding = true;
u64 config;

- if (!pt->tsc_bit || !pt->cap_user_time_zero)
+ if (!pt->tsc_bit || !pt->cap_user_time_zero || pt->synth_opts.timeless_decoding)
return true;

evlist__for_each_entry(pt->session->evlist, evsel) {
--
2.17.1
\
 
 \ /
  Last update: 2021-04-29 14:59    [W:0.167 / U:2.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site