ceph/src/seastar/tests/unit/alien_test.cc

   1 // -*- mode:C++; tab-width:4; c-basic-offset:4; indent-tabs-mode:nil -*-
   2 /*
   3  * This file is open source software, licensed to you under the terms
   4  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   5  * distributed with this work for additional information regarding copyright
   6  * ownership.  You may not use this file except in compliance with the License.
   7  *
   8  * You may obtain a copy of the License at
   9  *
  10  *   http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing,
  13  * software distributed under the License is distributed on an
  14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  15  * KIND, either express or implied.  See the License for the
  16  * specific language governing permissions and limitations
  17  * under the License.
  18  */
  19 /*
  20  * Copyright (C) 2018 Red Hat
  21  */
  22
  23 #include <future>
  24 #include <numeric>
  25 #include <iostream>
  26 #include <seastar/core/alien.hh>
  27 #include <seastar/core/smp.hh>
  28 #include <seastar/core/app-template.hh>
  29 #include <seastar/core/posix.hh>
  30 #include <seastar/core/reactor.hh>
  31 #include <seastar/util/later.hh>
  32
  33 using namespace seastar;
  34
  35 enum {
  36     ENGINE_READY = 24,
  37     ALIEN_DONE   = 42,
  38 };
  39
  40 int main(int argc, char** argv)
  41 {
  42     // we need a protocol that both seastar and alien understand.
  43     // and on which, a seastar future can wait.
  44     int engine_ready_fd = eventfd(0, 0);
  45     auto alien_done = file_desc::eventfd(0, 0);
  46     seastar::app_template app;
  47
  48     // use the raw fd, because seastar engine want to take over the fds, if it
  49     // polls on them.
  50     auto zim = std::async([&app, engine_ready_fd,
  51                            alien_done=alien_done.get()] {
  52         eventfd_t result = 0;
  53         // wait until the seastar engine is ready
  54         int r = ::eventfd_read(engine_ready_fd, &result);
  55         if (r < 0) {
  56             return -EINVAL;
  57         }
  58         if (result != ENGINE_READY) {
  59             return -EINVAL;
  60         }
  61         std::vector<std::future<int>> counts;
  62         for (auto i : boost::irange(0u, smp::count)) {
  63             // send messages from alien.
  64             counts.push_back(alien::submit_to(app.alien(), i, [i] {
  65                 return seastar::make_ready_future<int>(i);
  66             }));
  67         }
  68         // std::future<void>
  69         alien::submit_to(app.alien(), 0, [] {
  70             return seastar::make_ready_future<>();
  71         }).wait();
  72         int total = 0;
  73         for (auto& count : counts) {
  74             total += count.get();
  75         }
  76         // i am done. dismiss the engine
  77         ::eventfd_write(alien_done, ALIEN_DONE);
  78         return total;
  79     });
  80
  81     eventfd_t result = 0;
  82     app.run(argc, argv, [&] {
  83         return seastar::now().then([engine_ready_fd] {
  84             // engine ready!
  85             ::eventfd_write(engine_ready_fd, ENGINE_READY);
  86             return seastar::now();
  87         }).then([alien_done = std::move(alien_done), &result]() mutable {
  88             return do_with(seastar::pollable_fd(std::move(alien_done)), [&result] (pollable_fd& alien_done_fds) {
  89                 // check if alien has dismissed me.
  90                 return alien_done_fds.readable().then([&result, &alien_done_fds] {
  91                     auto ret = alien_done_fds.get_file_desc().read(&result, sizeof(result));
  92                     return make_ready_future<size_t>(*ret);
  93                 });
  94             });
  95         }).then([&result](size_t n) {
  96             if (n != sizeof(result)) {
  97                 throw std::runtime_error("read from eventfd failed");
  98             }
  99             if (result != ALIEN_DONE) {
 100                 throw std::logic_error("alien failed to dismiss me");
 101             }
 102             return seastar::now();
 103         }).handle_exception([](auto ep) {
 104             std::cerr << "Error: " << ep << std::endl;
 105         }).finally([] {
 106             seastar::engine().exit(0);
 107         });
 108     });
 109     int total = zim.get();
 110     const auto shards = boost::irange(0u, smp::count);
 111     auto expected = std::accumulate(std::begin(shards), std::end(shards), 0);
 112     if (total != expected) {
 113         std::cerr << "Bad total: " << total << " != " << expected << std::endl;
 114         return 1;
 115     }
 116 }