Merge "debuggerd: add pause time benchmark." am: 1b4ab8bc39 am: eba1be0d98 (0c3ed234) · Commits · e / os / android_system_core

debuggerd/Android.bp

+10 −0

Original line number	Diff line number	Diff line
		@@ -218,6 +218,16 @@ cc_test {
		},
		}

		cc_benchmark {
		name: "debuggerd_benchmark",
		defaults: ["debuggerd_defaults"],
		srcs: ["debuggerd_benchmark.cpp"],
		shared_libs: [
		"libbase",
		"libdebuggerd_client",
		],
		}

		cc_binary {
		name: "crash_dump",
		srcs: [

debuggerd/debuggerd_benchmark.cpp

0 → 100644

+128 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright 2017, 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.
		*/

		#include <err.h>
		#include <errno.h>
		#include <sched.h>
		#include <string.h>
		#include <sys/wait.h>
		#include <unistd.h>

		#include <chrono>
		#include <thread>

		#include <benchmark/benchmark.h>
		#include <debuggerd/client.h>

		using namespace std::chrono_literals;

		static_assert(std::chrono::high_resolution_clock::is_steady);

		enum class ThreadState { Starting, Started, Stopping };

		static void SetScheduler() {
		struct sched_param param {
		.sched_priority = 1,
		};

		if (sched_setscheduler(getpid(), SCHED_FIFO, &param) != 0) {
		fprintf(stderr, "failed to set scheduler to SCHED_FIFO: %s", strerror(errno));
		}
		}

		static std::chrono::duration<double> GetMaximumPause(std::atomic<ThreadState>& state) {
		std::chrono::duration<double> max_diff(0);

		const auto begin = std::chrono::high_resolution_clock::now();
		auto last = begin;
		state.store(ThreadState::Started);
		while (state.load() != ThreadState::Stopping) {
		auto now = std::chrono::high_resolution_clock::now();

		auto diff = now - last;
		if (diff > max_diff) {
		max_diff = diff;
		}

		last = now;
		}

		return max_diff;
		}

		static void PerformDump() {
		pid_t target = getpid();
		pid_t forkpid = fork();
		if (forkpid == -1) {
		err(1, "fork failed");
		} else if (forkpid != 0) {
		int status;
		pid_t pid = waitpid(forkpid, &status, 0);
		if (pid == -1) {
		err(1, "waitpid failed");
		} else if (!WIFEXITED(status)) {
		err(1, "child didn't exit");
		} else if (WEXITSTATUS(status) != 0) {
		errx(1, "child exited with non-zero status %d", WEXITSTATUS(status));
		}
		} else {
		android::base::unique_fd output_fd(open("/dev/null", O_WRONLY \| O_CLOEXEC));
		if (output_fd == -1) {
		err(1, "failed to open /dev/null");
		}

		if (!debuggerd_trigger_dump(target, kDebuggerdNativeBacktrace, 1000, std::move(output_fd))) {
		errx(1, "failed to trigger dump");
		}

		_exit(0);
		}
		}

		template <typename Fn>
		static void BM_maximum_pause_impl(benchmark::State& state, const Fn& function) {
		SetScheduler();

		for (auto _ : state) {
		std::chrono::duration<double> max_pause;
		std::atomic<ThreadState> thread_state(ThreadState::Starting);
		auto thread = std::thread([&]() { max_pause = GetMaximumPause(thread_state); });

		while (thread_state != ThreadState::Started) {
		std::this_thread::sleep_for(1ms);
		}

		function();

		thread_state = ThreadState::Stopping;
		thread.join();

		state.SetIterationTime(max_pause.count());
		}
		}

		static void BM_maximum_pause_noop(benchmark::State& state) {
		BM_maximum_pause_impl(state, []() {});
		}

		static void BM_maximum_pause_debuggerd(benchmark::State& state) {
		BM_maximum_pause_impl(state, []() { PerformDump(); });
		}

		BENCHMARK(BM_maximum_pause_noop)->Iterations(128)->UseManualTime();
		BENCHMARK(BM_maximum_pause_debuggerd)->Iterations(128)->UseManualTime();

		BENCHMARK_MAIN();