From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@redhat.com>, Andi Kleen <ak@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH V2 03/12] perf intel-pt: Support Z itrace option for timeless decoding
Date: Fri, 30 Apr 2021 10:03:00 +0300 [thread overview]
Message-ID: <20210430070309.17624-4-adrian.hunter@intel.com> (raw)
In-Reply-To: <20210430070309.17624-1-adrian.hunter@intel.com>
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) {
--
2.25.1
next prev parent reply other threads:[~2021-04-30 7:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 7:02 [PATCH V2 00/12] perf intel-pt: Add more support for VMs Adrian Hunter
2021-04-30 7:02 ` [PATCH V2 01/12] perf auxtrace: Add Z itrace option for timeless decoding Adrian Hunter
2021-04-30 7:02 ` [PATCH V2 02/12] perf intel-pt: Move synth_opts initialization earlier Adrian Hunter
2021-04-30 7:03 ` Adrian Hunter [this message]
2021-04-30 7:03 ` [PATCH V2 04/12] perf inject: Add facility to do in place update Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 05/12] perf inject: Add --vm-time-correlation option Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 06/12] perf auxtrace: Allow buffers to be mapped read / write Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 07/12] perf intel-pt: Let overlap detection handle VM timestamps Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 08/12] perf intel-pt: Add a tree for VMCS information Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 09/12] perf intel-pt: Pass the first timestamp to the decoder Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 10/12] perf intel-pt: Better 7-byte timestamp wraparound logic Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 11/12] perf intel-pt: Add VM Time Correlation to decoder Adrian Hunter
2021-04-30 7:03 ` [PATCH V2 12/12] perf intel-pt: Parse VM Time Correlation options and set up decoding Adrian Hunter
2021-04-30 21:29 ` [PATCH V2 00/12] perf intel-pt: Add more support for VMs Andi Kleen
2021-05-03 15:09 ` Arnaldo Carvalho de Melo
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