1 files changed, 179 insertions, 0 deletions
diff --git a/src/seastar/demos/scheduling_group_demo.cc b/src/seastar/demos/scheduling_group_demo.cc
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+++ b/src/seastar/demos/scheduling_group_demo.cc
@@ -0,0 +1,179 @@
+/*
+ * This file is open source software, licensed to you under the terms
+ * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
+ * distributed with this work for additional information regarding copyright
+ * ownership.  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.
+ */
+/*
+ * Copyright (C) 2016 Scylla DB Ltd
+ */
+
+
+#include <seastar/core/app-template.hh>
+#include <seastar/core/future.hh>
+#include <seastar/core/scheduling.hh>
+#include <seastar/core/thread.hh>
+#include <seastar/core/future-util.hh>
+#include <seastar/core/reactor.hh>
+#include <seastar/util/defer.hh>
+#include <chrono>
+#include <cmath>
+
+using namespace seastar;
+using namespace std::chrono_literals;
+
+template <typename Func, typename Duration>
+future<>
+compute_intensive_task(Duration duration, unsigned& counter, Func func) {
+    auto end = std::chrono::steady_clock::now() + duration;
+    while (std::chrono::steady_clock::now() < end) {
+        func();
+    }
+    ++counter;
+    return make_ready_future<>();
+}
+
+future<>
+heavy_task(unsigned& counter) {
+    return compute_intensive_task(1ms, counter, [] {
+        static thread_local double x = 1;
+        x = std::exp(x) / 3;
+    });
+}
+
+future<>
+light_task(unsigned& counter) {
+    return compute_intensive_task(100us, counter, [] {
+        static thread_local double x = 0.1;
+        x = std::log(x + 1);
+    });
+}
+
+future<>
+medium_task(unsigned& counter) {
+    return compute_intensive_task(400us, counter, [] {
+        static thread_local double x = 0.1;
+        x = std::cos(x);
+    });
+}
+
+using done_func = std::function<bool ()>;
+
+future<>
+run_compute_intensive_tasks(seastar::scheduling_group sg, done_func done, unsigned concurrency, unsigned& counter, std::function<future<> (unsigned& counter)> task) {
+    return seastar::async([task, sg, concurrency, done, &counter] {
+        while (!done()) {
+            parallel_for_each(boost::irange(0u, concurrency), [task, sg, &counter] (unsigned i) {
+                return with_scheduling_group(sg, [task, &counter] {
+                    return task(counter);
+                });
+            }).get();
+        }
+    });
+}
+
+future<>
+run_compute_intensive_tasks_in_threads(seastar::scheduling_group sg, done_func done, unsigned concurrency, unsigned& counter, std::function<future<> (unsigned& counter)> task) {
+    auto attr = seastar::thread_attributes();
+    attr.sched_group = sg;
+    return parallel_for_each(boost::irange(0u, concurrency), [attr, done, &counter, task] (unsigned i) {
+        return seastar::async(attr, [done, &counter, task] {
+            while (!done()) {
+                task(counter).get();
+            }
+        });
+    });
+}
+
+future<>
+run_with_duty_cycle(float utilization, std::chrono::steady_clock::duration period, done_func done, std::function<future<> (done_func done)> task) {
+    return seastar::async([=] {
+        bool duty_toggle = true;
+        auto t0 = std::chrono::steady_clock::now();
+        condition_variable cv;
+        timer<> tmr_on([&] { duty_toggle = true; cv.signal(); });
+        timer<> tmr_off([&] { duty_toggle = false; });
+        tmr_on.arm(t0, period);
+        tmr_off.arm(t0 + std::chrono::duration_cast<decltype(t0)::duration>(period * utilization), period);
+        auto combined_done = [&] {
+            return done() || !duty_toggle;
+        };
+        while (!done()) {
+            while (!combined_done()) {
+                task(std::cref(combined_done)).get();
+            }
+            cv.wait([&] {
+                return done() || duty_toggle;
+            }).get();
+        }
+        tmr_on.cancel();
+        tmr_off.cancel();
+    });
+}
+
+#include <fenv.h>
+
+template <typename T>
+auto var_fn(T& var) {
+    return [&var] { return var; };
+}
+
+int main(int ac, char** av) {
+    app_template app;
+    return app.run(ac, av, [] {
+        return seastar::async([] {
+            auto sg100 = seastar::create_scheduling_group("sg100", 100).get0();
+            auto ksg100 = seastar::defer([&] { seastar::destroy_scheduling_group(sg100).get(); });
+            auto sg20 = seastar::create_scheduling_group("sg20", 20).get0();
+            auto ksg20 = seastar::defer([&] { seastar::destroy_scheduling_group(sg20).get(); });
+            auto sg50 = seastar::create_scheduling_group("sg50", 50).get0();
+            auto ksg50 = seastar::defer([&] { seastar::destroy_scheduling_group(sg50).get(); });
+
+            bool done = false;
+            auto end = timer<>([&done] {
+                done = true;
+            });
+
+            end.arm(10s);
+            unsigned ctr100 = 0, ctr20 = 0, ctr50 = 0;
+            fmt::print("running three scheduling groups with 100% duty cycle each:\n");
+            when_all(
+                    run_compute_intensive_tasks(sg100, var_fn(done), 5, ctr100, heavy_task),
+                    run_compute_intensive_tasks(sg20, var_fn(done), 3, ctr20, light_task),
+                    run_compute_intensive_tasks_in_threads(sg50, var_fn(done), 2, ctr50, medium_task)
+                    ).get();
+            fmt::print("{:10} {:15} {:10} {:12} {:8}\n", "shares", "task_time (us)", "executed", "runtime (ms)", "vruntime");
+            fmt::print("{:10d} {:15d} {:10d} {:12d} {:8.2f}\n", 100, 1000, ctr100, ctr100 * 1000 / 1000, ctr100 * 1000 / 1000 / 100.);
+            fmt::print("{:10d} {:15d} {:10d} {:12d} {:8.2f}\n", 20, 100, ctr20, ctr20 * 100 / 1000, ctr20 * 100 / 1000 / 20.);
+            fmt::print("{:10d} {:15d} {:10d} {:12d} {:8.2f}\n", 50, 400, ctr50, ctr50 * 400 / 1000, ctr50 * 400 / 1000 / 50.);
+            fmt::print("\n");
+
+            fmt::print("running two scheduling groups with 100%/50% duty cycles (period=1s:\n");
+            unsigned ctr100_2 = 0, ctr50_2 = 0;
+            done = false;
+            end.arm(10s);
+            when_all(
+                    run_compute_intensive_tasks(sg50, var_fn(done), 5, ctr50_2, heavy_task),
+                    run_with_duty_cycle(0.5, 1s, var_fn(done), [=, &ctr100_2] (done_func done) {
+                        return run_compute_intensive_tasks(sg100, done, 4, ctr100_2, heavy_task);
+                    })
+            ).get();
+            fmt::print("{:10} {:10} {:15} {:10} {:12} {:8}\n", "shares", "duty", "task_time (us)", "executed", "runtime (ms)", "vruntime");
+            fmt::print("{:10d} {:10d} {:15d} {:10d} {:12d} {:8.2f}\n", 100, 50, 1000, ctr100_2, ctr100_2 * 1000 / 1000, ctr100_2 * 1000 / 1000 / 100.);
+            fmt::print("{:10d} {:10d} {:15d} {:10d} {:12d} {:8.2f}\n", 50, 100, 400, ctr50_2, ctr50_2 * 1000 / 1000, ctr50_2 * 1000 / 1000 / 50.);
+
+            return 0;
+        });
+    });
+}