instruments: Add Perfetto instrument

Add an instrument that uses devlib's PerfettoCollector to collect a
Perfetto trace during the execution of a workload.
The instrument takes a path to a Perfetto config file which specifies
how Perfetto should be configured for the tracing.

Signed-off-by: Kajetan Puchalski <kajetan.puchalski@arm.com>

wa/instruments/perfetto.py

@@ -0,0 +1,101 @@
+#    Copyright 2023 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import os
+
+from devlib import PerfettoCollector
+
+from wa import Instrument, Parameter
+from wa.framework.instrument import very_slow, is_installed
+from wa.framework.exception import InstrumentError
+
+OUTPUT_PERFETTO_TRACE = 'devlib-trace.perfetto-trace'
+PERFETTO_CONFIG_FILE = 'config.pbtx'
+
+
+class PerfettoInstrument(Instrument):
+    name = 'perfetto'
+    description = """
+        perfetto is an instrument that interacts with Google's Perfetto tracing
+        infrastructure.
+
+        From Perfetto's website:
+        Perfetto is a production-grade open-source stack for performance instrumentation and trace analysis.
+        It offers services and libraries for recording system-level and app-level traces, native + java heap profiling,
+        a library for analyzing traces using SQL and a web-based UI to visualize and explore multi-GB traces.
+
+        The instrument either requires Perfetto to be present on the target device or the standalone tracebox binary
+        to be built from source and included in devlib's Package Bin directory.
+        For more information, consult the PerfettoCollector documentation in devlib.
+
+        More information can be found on https://perfetto.dev/
+    """
+
+    parameters = [
+        Parameter('config', kind=str, mandatory=True,
+                  description="""
+                  Path to the Perfetto trace config file.
+
+                  All the Perfetto-specific tracing configuration should be done inside
+                  that file. This config option should just take a full
+                  filesystem path to where the config can be found.
+                  """),
+        Parameter('force_tracebox', kind=bool, default=False,
+                  description="""
+                  Install tracebox even if traced is already running on the target device.
+                  If set to true, the tracebox binary needs to be placed in devlib's Package Bin directory.
+                  """)
+    ]
+
+    def __init__(self, target, **kwargs):
+        super(PerfettoInstrument, self).__init__(target, **kwargs)
+        self.collector = None
+
+    def initialize(self, context):  # pylint: disable=unused-argument
+        self.target_config = self.target.path.join(self.target.working_directory, PERFETTO_CONFIG_FILE)
+        # push the config file to target
+        self.target.push(self.config, self.target_config)
+        collector_params = dict(
+            config=self.target_config,
+            force_tracebox=self.force_tracebox
+        )
+        self.collector = PerfettoCollector(self.target, **collector_params)
+
+    @very_slow
+    def start(self, context):  # pylint: disable=unused-argument
+        self.collector.start()
+
+    @very_slow
+    def stop(self, context):  # pylint: disable=unused-argument
+        self.collector.stop()
+
+    def update_output(self, context):
+        self.logger.info('Extracting Perfetto trace from target...')
+        outfile = os.path.join(context.output_directory, OUTPUT_PERFETTO_TRACE)
+        self.collector.set_output(outfile)
+        self.collector.get_data()
+        context.add_artifact('perfetto-bin', outfile, 'data')
+
+    def teardown(self, context):  # pylint: disable=unused-argument
+        self.target.remove(self.collector.target_output_file)
+
+    def finalize(self, context):  # pylint: disable=unused-argument
+        self.target.remove(self.target_config)
+
+    def validate(self):
+        if is_installed('trace-cmd'):
+            raise InstrumentError('perfetto cannot be used at the same time as trace-cmd')
+        if not os.path.isfile(self.config):
+            raise InstrumentError('perfetto config file not found at "{}"'.format(self.config))

wa/instruments/trace_cmd.py

@@ -22,7 +22,7 @@ from devlib import FtraceCollector
 
 from wa import Instrument, Parameter
 from wa.framework import signal
-from wa.framework.instrument import very_slow
+from wa.framework.instrument import very_slow, is_installed
 from wa.framework.exception import InstrumentError
 from wa.utils.types import list_of_strings
 from wa.utils.misc import which
@@ -235,6 +235,8 @@ class TraceCmdInstrument(Instrument):
     def validate(self):
         if self.report and not self.report_on_target and not which('trace-cmd'):
             raise InstrumentError('trace-cmd is not in PATH; is it installed?')
+        if is_installed('perfetto'):
+            raise InstrumentError('trace-cmd cannot be used at the same time as perfetto')
 
     def mark_start(self, context):
         if self.is_enabled: