97 lines
2.9 KiB
C++
97 lines
2.9 KiB
C++
/*
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* This file is open source software, licensed to you under the terms
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* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
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* distributed with this work for additional information regarding copyright
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* ownership. You may not use this file except in compliance with the License.
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*
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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#include <experimental/optional>
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#include "core/thread.hh"
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#include "core/semaphore.hh"
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#include "core/app-template.hh"
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#include "core/do_with.hh"
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#include "core/distributed.hh"
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#include "core/sleep.hh"
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using namespace seastar;
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using namespace std::chrono_literals;
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class context_switch_tester {
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uint64_t _switches{0};
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semaphore _s1{0};
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semaphore _s2{0};
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bool _done1{false};
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bool _done2{false};
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thread _t1{[this] { main1(); }};
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thread _t2{[this] { main2(); }};
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private:
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void main1() {
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while (!_done1) {
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_s1.wait().get();
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++_switches;
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_s2.signal();
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}
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_done2 = true;
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}
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void main2() {
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while (!_done2) {
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_s2.wait().get();
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++_switches;
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_s1.signal();
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}
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}
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public:
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void begin_measurement() {
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_s1.signal();
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}
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future<uint64_t> measure() {
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_done1 = true;
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return _t1.join().then([this] {
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return _t2.join();
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}).then([this] {
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return _switches;
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});
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}
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future<> stop() {
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return make_ready_future<>();
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}
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};
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int main(int ac, char** av) {
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static const auto test_time = 5s;
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return app_template().run(ac, av, [] {
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return do_with(distributed<context_switch_tester>(), [] (distributed<context_switch_tester>& dcst) {
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return dcst.start().then([&dcst] {
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return dcst.invoke_on_all(&context_switch_tester::begin_measurement);
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}).then([] {
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return sleep(test_time);
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}).then([&dcst] {
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return dcst.map_reduce0(std::mem_fn(&context_switch_tester::measure), uint64_t(), std::plus<uint64_t>());
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}).then([] (uint64_t switches) {
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switches /= smp::count;
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print("context switch time: %5.1f ns\n",
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double(std::chrono::duration_cast<std::chrono::nanoseconds>(test_time).count()) / switches);
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}).then([&dcst] {
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return dcst.stop();
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}).then([] {
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engine_exit(0);
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});
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});
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});
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}
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