PerfettoCapture.kt
/*
* Copyright 2020 The Android Open Source Project
*
* 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.
*/
package androidx.benchmark.macro.perfetto
import android.os.Build
import androidx.annotation.RequiresApi
import androidx.annotation.RestrictTo
import androidx.benchmark.Outputs
import androidx.benchmark.macro.userspaceTrace
import java.io.File
/**
* Enables capturing a Perfetto trace from a test on Q+ devices.
*
* It's possible to support API 28, but there are a few issues to resolve:
* - Use binary config protos
* - May need to distribute perfetto binary, with atrace workaround
* - App tags are not available, due to lack of `<profileable shell=true>`. Can potentially hack
* around this for individual tags within test infra as needed.
*
* @suppress
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
@RequiresApi(21)
public class PerfettoCapture(
unbundled: Boolean = Build.VERSION.SDK_INT in 21..28
) {
private val helper: PerfettoHelper = PerfettoHelper(unbundled)
/**
* Kill perfetto process, if it is running.
*/
public fun cancel() {
if (helper.isPerfettoRunning()) {
helper.stopPerfetto()
}
}
/**
* Start collecting perfetto trace.
*
* TODO: provide configuration options
*/
public fun start(packages: List<String>) = userspaceTrace("start perfetto") {
// Write binary proto to dir that shell can read
// TODO: cache on disk
val configProtoFile = File(Outputs.dirUsableByAppAndShell, "trace_config.pb")
try {
userspaceTrace("write config") {
val atraceApps = if (Build.VERSION.SDK_INT <= 28) {
packages
} else {
listOf("*")
}
configProtoFile.writeBytes(perfettoConfig(atraceApps).validateAndEncode())
}
userspaceTrace("start perfetto process") {
helper.startCollecting(configProtoFile.absolutePath, false)
}
} finally {
configProtoFile.delete()
}
}
/**
* Stop collection, and record trace to the specified file path.
*
* @param destinationPath Absolute path to write perfetto trace to. Must be shell-writable,
* such as result of `context.getExternalFilesDir(null)` or other similar `external` paths.
*/
public fun stop(destinationPath: String) = userspaceTrace("stop perfetto") {
// Wait time determined empirically by running a trivial startup test (3 iterations) 200
// times, and validating no metric capture failures.
if (!helper.stopCollecting(500, destinationPath)) {
// TODO: move internal failures to be exceptions
throw IllegalStateException("Unable to store perfetto trace in $destinationPath")
}
}
}