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/app-template.hh>
  28 #include <seastar/core/posix.hh>
  29 #include <seastar/core/reactor.hh>
  30
  31 using namespace seastar;
  32
  33 enum {
  34     ENGINE_READY = 24,
  35     ALIEN_DONE   = 42,
  36 };
  37
  38 int main(int argc, char** argv)
  39 {
  40     // we need a protocol that both seastar and alien understand.
  41     // and on which, a seastar future can wait.
  42     int engine_ready_fd = eventfd(0, 0);
  43     auto alien_done = file_desc::eventfd(0, 0);
  44
  45     // use the raw fd, because seastar engine want to take over the fds, if it
  46     // polls on them.
  47     auto zim = std::async([engine_ready_fd,
  48                            alien_done=alien_done.get()] {
  49         eventfd_t result = 0;
  50         // wait until the seastar engine is ready
  51         int r = ::eventfd_read(engine_ready_fd, &result);
  52         if (r < 0) {
  53             return -EINVAL;
  54         }
  55         if (result != ENGINE_READY) {
  56             return -EINVAL;
  57         }
  58         std::vector<std::future<int>> counts;
  59         for (auto i : boost::irange(0u, smp::count)) {
  60             // send messages from alien.
  61             counts.push_back(alien::submit_to(i, [i] {
  62                 return seastar::make_ready_future<int>(i);
  63             }));
  64         }
  65         int total = 0;
  66         for (auto& count : counts) {
  67             total += count.get();
  68         }
  69         // i am done. dismiss the engine
  70         ::eventfd_write(alien_done, ALIEN_DONE);
  71         return total;
  72     });
  73
  74     seastar::app_template app;
  75     seastar::pollable_fd_state alien_done_fds{std::move(alien_done)};
  76     eventfd_t result = 0;
  77     app.run(argc, argv, [&] {
  78         return seastar::now().then([engine_ready_fd] {
  79             // engine ready!
  80             ::eventfd_write(engine_ready_fd, ENGINE_READY);
  81             return seastar::now();
  82         }).then([&alien_done_fds, &result]() {
  83             // check if alien has dismissed me.
  84             return seastar::engine().read_some(alien_done_fds, &result, sizeof(result));
  85         }).then([&result](size_t n) {
  86             if (n != sizeof(result)) {
  87                 throw std::runtime_error("read from eventfd failed");
  88             }
  89             if (result != ALIEN_DONE) {
  90                 throw std::logic_error("alien failed to dismiss me");
  91             }
  92             return seastar::now();
  93         }).handle_exception([](auto ep) {
  94             std::cerr << "Error: " << ep << std::endl;
  95         }).finally([] {
  96             seastar::engine().exit(0);
  97         });
  98     });
  99     int total = zim.get();
 100     const auto shards = boost::irange(0u, smp::count);
 101     auto expected = std::accumulate(std::begin(shards), std::end(shards), 0);
 102     if (total != expected) {
 103         std::cerr << "Bad total: " << total << " != " << expected << std::endl;
 104         return 1;
 105     }
 106 }