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From: James Clark <james.clark@arm.com>
To: linux-perf-users@vger.kernel.org,
	gankulkarni@os.amperecomputing.com,
	scclevenger@os.amperecomputing.com,
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Cc: James Clark <james.clark@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>,
	Leo Yan <leo.yan@linux.dev>,
	linux-arm-kernel@lists.infradead.org,
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Subject: [PATCH 02/17] perf auxtrace: Allow number of queues to be specified
Date: Mon, 29 Apr 2024 16:21:47 +0100
Message-Id: <20240429152207.479221-3-james.clark@arm.com>
In-Reply-To: <20240429152207.479221-1-james.clark@arm.com>
References: <20240429152207.479221-1-james.clark@arm.com>
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Currently it's only possible to initialize with the default number of
queues and then use auxtrace_queues__add_event() to grow the array. But
that's problematic if you don't have a real event to pass into that
function yet.

The queues hold a void *priv member to store custom state, and for
Coresight we want to create decoders upfront before receiving data, so
add a new function that allows pre-allocating queues. One reason to do
this is because we might need to store metadata (HW_ID events) that
effects other queues, but never actually receive auxtrace data on that
queue.

Signed-off-by: James Clark <james.clark@arm.com>
---
 tools/perf/util/auxtrace.c | 9 +++++++--
 tools/perf/util/auxtrace.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index 3684e6009b63..563b6c4fca31 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -218,15 +218,20 @@ static struct auxtrace_queue *auxtrace_alloc_queue_array(unsigned int nr_queues)
 	return queue_array;
 }
 
-int auxtrace_queues__init(struct auxtrace_queues *queues)
+int auxtrace_queues__init_nr(struct auxtrace_queues *queues, int nr_queues)
 {
-	queues->nr_queues = AUXTRACE_INIT_NR_QUEUES;
+	queues->nr_queues = nr_queues;
 	queues->queue_array = auxtrace_alloc_queue_array(queues->nr_queues);
 	if (!queues->queue_array)
 		return -ENOMEM;
 	return 0;
 }
 
+int auxtrace_queues__init(struct auxtrace_queues *queues)
+{
+	return auxtrace_queues__init_nr(queues, AUXTRACE_INIT_NR_QUEUES);
+}
+
 static int auxtrace_queues__grow(struct auxtrace_queues *queues,
 				 unsigned int new_nr_queues)
 {
diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index 55702215a82d..8a6ec9565835 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -521,6 +521,7 @@ int auxtrace_mmap__read_snapshot(struct mmap *map,
 				 struct perf_tool *tool, process_auxtrace_t fn,
 				 size_t snapshot_size);
 
+int auxtrace_queues__init_nr(struct auxtrace_queues *queues, int nr_queues);
 int auxtrace_queues__init(struct auxtrace_queues *queues);
 int auxtrace_queues__add_event(struct auxtrace_queues *queues,
 			       struct perf_session *session,
-- 
2.34.1