linux-kernel - [PATCH 17/25] perf intel-pt: Force 'quick' mode when TNT is disabled

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Date:   Mon, 24 Jan 2022 10:41:53 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 17/25] perf intel-pt: Force 'quick' mode when TNT is disabled

It is not possible to walk the executable code without TNT packets, so
force 'quick' mode when TNT is disabled, because 'quick' mode does not walk
the code.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/intel-pt.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index d76e4b865cb0..ec43d364d0de 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -50,6 +50,7 @@
 #define INTEL_PT_CFG_PWR_EVT_EN	BIT_ULL(4)
 #define INTEL_PT_CFG_BRANCH_EN	BIT_ULL(13)
 #define INTEL_PT_CFG_EVT_EN	BIT_ULL(31)
+#define INTEL_PT_CFG_TNT_DIS	BIT_ULL(55)
 
 struct range {
 	u64 start;
@@ -972,6 +973,19 @@ static bool intel_pt_branch_enable(struct intel_pt *pt)
 	return true;
 }
 
+static bool intel_pt_disabled_tnt(struct intel_pt *pt)
+{
+	struct evsel *evsel;
+	u64 config;
+
+	evlist__for_each_entry(pt->session->evlist, evsel) {
+		if (intel_pt_get_config(pt, &evsel->core.attr, &config) &&
+		    config & INTEL_PT_CFG_TNT_DIS)
+			return true;
+	}
+	return false;
+}
+
 static unsigned int intel_pt_mtc_period(struct intel_pt *pt)
 {
 	struct evsel *evsel;
@@ -1227,6 +1241,10 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
 	params.first_timestamp = pt->first_timestamp;
 	params.max_loops = pt->max_loops;
 
+	/* Cannot walk code without TNT, so force 'quick' mode */
+	if (params.branch_enable && intel_pt_disabled_tnt(pt) && !params.quick)
+		params.quick = 1;
+
 	if (pt->filts.cnt > 0)
 		params.pgd_ip = intel_pt_pgd_ip;
 
-- 
2.25.1