[PATCH V2 06/12] perf intel-pt: Use itrace error flags to suppress some errors

From: Adrian Hunter <adrian.hunter@intel.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Andi Kleen <ak@linux.intel.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH V2 06/12] perf intel-pt: Use itrace error flags to suppress some errors
Date: Fri, 10 Jul 2020 18:10:58 +0300	[thread overview]
Message-ID: <20200710151104.15137-7-adrian.hunter@intel.com> (raw)
In-Reply-To: <20200710151104.15137-1-adrian.hunter@intel.com>

The itrace "e" option may be followed by flags which affect what errors
will or will not be reported.  Each flag must be preceded by either '+' or '-'.
The flags supported by Intel PT are:
		-o	Suppress overflow errors
		-l	Suppress trace data lost errors
For example, for errors but not overflow or data lost errors:

	--itrace=e-o-l

Suppressing those errors can be useful for testing and debugging
because they are not due to decoding.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 tools/perf/Documentation/perf-intel-pt.txt | 9 ++++++++-
 tools/perf/util/intel-pt.c                 | 9 +++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt
index f4cd49a7fcdb..20ac592a2641 100644
--- a/tools/perf/Documentation/perf-intel-pt.txt
+++ b/tools/perf/Documentation/perf-intel-pt.txt
@@ -871,7 +871,14 @@ Developer Manuals.
 
 Error events show where the decoder lost the trace.  Error events
 are quite important.  Users must know if what they are seeing is a complete
-picture or not.
+picture or not. The "e" option may be followed by flags which affect what errors
+will or will not be reported.  Each flag must be preceded by either '+' or '-'.
+The flags supported by Intel PT are:
+		-o	Suppress overflow errors
+		-l	Suppress trace data lost errors
+For example, for errors but not overflow or data lost errors:
+
+	--itrace=e-o-l
 
 The "d" option will cause the creation of a file "intel_pt.log" containing all
 decoded packets and instructions.  Note that this option slows down the decoder
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index f09d4cfcd0fd..a1cb6a284a2b 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -1862,6 +1862,15 @@ static int intel_pt_synth_error(struct intel_pt *pt, int code, int cpu,
 	char msg[MAX_AUXTRACE_ERROR_MSG];
 	int err;
 
+	if (pt->synth_opts.error_minus_flags) {
+		if (code == INTEL_PT_ERR_OVR &&
+		    pt->synth_opts.error_minus_flags & AUXTRACE_ERR_FLG_OVERFLOW)
+			return 0;
+		if (code == INTEL_PT_ERR_LOST &&
+		    pt->synth_opts.error_minus_flags & AUXTRACE_ERR_FLG_DATA_LOST)
+			return 0;
+	}
+
 	intel_pt__strerror(code, msg, MAX_AUXTRACE_ERROR_MSG);
 
 	auxtrace_synth_error(&event.auxtrace_error, PERF_AUXTRACE_ERROR_ITRACE,
-- 
2.17.1

