Merge branch 'master' into iptables

1 files changed, 350 insertions, 0 deletions

diff --git a/test/perf/linux/fork_benchmark.cc b/test/perf/linux/fork_benchmark.cc
new file mode 100644
index 000000000..84fdbc8a0
--- /dev/null
+++ b/test/perf/linux/fork_benchmark.cc
@@ -0,0 +1,350 @@
+// Copyright 2020 The gVisor Authors.
+//
+// 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 <unistd.h>
+
+#include "gtest/gtest.h"
+#include "absl/synchronization/barrier.h"
+#include "benchmark/benchmark.h"
+#include "test/util/cleanup.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/logging.h"
+#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+constexpr int kBusyMax = 250;
+
+// Do some CPU-bound busy-work.
+int busy(int max) {
+  // Prevent the compiler from optimizing this work away,
+  volatile int count = 0;
+
+  for (int i = 1; i < max; i++) {
+    for (int j = 2; j < i / 2; j++) {
+      if (i % j == 0) {
+        count++;
+      }
+    }
+  }
+
+  return count;
+}
+
+void BM_CPUBoundUniprocess(benchmark::State& state) {
+  for (auto _ : state) {
+    busy(kBusyMax);
+  }
+}
+
+BENCHMARK(BM_CPUBoundUniprocess);
+
+void BM_CPUBoundAsymmetric(benchmark::State& state) {
+  const size_t max = state.max_iterations;
+  pid_t child = fork();
+  if (child == 0) {
+    for (int i = 0; i < max; i++) {
+      busy(kBusyMax);
+    }
+    _exit(0);
+  }
+  ASSERT_THAT(child, SyscallSucceeds());
+  ASSERT_TRUE(state.KeepRunningBatch(max));
+
+  int status;
+  EXPECT_THAT(RetryEINTR(waitpid)(child, &status, 0), SyscallSucceeds());
+  EXPECT_TRUE(WIFEXITED(status));
+  EXPECT_EQ(0, WEXITSTATUS(status));
+  ASSERT_FALSE(state.KeepRunning());
+}
+
+BENCHMARK(BM_CPUBoundAsymmetric)->UseRealTime();
+
+void BM_CPUBoundSymmetric(benchmark::State& state) {
+  std::vector<pid_t> children;
+  auto child_cleanup = Cleanup([&] {
+    for (const pid_t child : children) {
+      int status;
+      EXPECT_THAT(RetryEINTR(waitpid)(child, &status, 0), SyscallSucceeds());
+      EXPECT_TRUE(WIFEXITED(status));
+      EXPECT_EQ(0, WEXITSTATUS(status));
+    }
+    ASSERT_FALSE(state.KeepRunning());
+  });
+
+  const int processes = state.range(0);
+  for (int i = 0; i < processes; i++) {
+    size_t cur = (state.max_iterations + (processes - 1)) / processes;
+    if ((state.iterations() + cur) >= state.max_iterations) {
+      cur = state.max_iterations - state.iterations();
+    }
+    pid_t child = fork();
+    if (child == 0) {
+      for (int i = 0; i < cur; i++) {
+        busy(kBusyMax);
+      }
+      _exit(0);
+    }
+    ASSERT_THAT(child, SyscallSucceeds());
+    if (cur > 0) {
+      // We can have a zero cur here, depending.
+      ASSERT_TRUE(state.KeepRunningBatch(cur));
+    }
+    children.push_back(child);
+  }
+}
+
+BENCHMARK(BM_CPUBoundSymmetric)->Range(2, 16)->UseRealTime();
+
+// Child routine for ProcessSwitch/ThreadSwitch.
+// Reads from readfd and writes the result to writefd.
+void SwitchChild(int readfd, int writefd) {
+  while (1) {
+    char buf;
+    int ret = ReadFd(readfd, &buf, 1);
+    if (ret == 0) {
+      break;
+    }
+    TEST_CHECK_MSG(ret == 1, "read failed");
+
+    ret = WriteFd(writefd, &buf, 1);
+    if (ret == -1) {
+      TEST_CHECK_MSG(errno == EPIPE, "unexpected write failure");
+      break;
+    }
+    TEST_CHECK_MSG(ret == 1, "write failed");
+  }
+}
+
+// Send bytes in a loop through a series of pipes, each passing through a
+// different process.
+//
+//  Proc 0        Proc 1
+//    * ----------> *
+//    ^   Pipe 1    |
+//    |             |
+//    | Pipe 0      | Pipe 2
+//    |             |
+//    |             |
+//    |   Pipe 3    v
+//    * <---------- *
+//  Proc 3        Proc 2
+//
+// This exercises context switching through multiple processes.
+void BM_ProcessSwitch(benchmark::State& state) {
+  // Code below assumes there are at least two processes.
+  const int num_processes = state.range(0);
+  ASSERT_GE(num_processes, 2);
+
+  std::vector<pid_t> children;
+  auto child_cleanup = Cleanup([&] {
+    for (const pid_t child : children) {
+      int status;
+      EXPECT_THAT(RetryEINTR(waitpid)(child, &status, 0), SyscallSucceeds());
+      EXPECT_TRUE(WIFEXITED(status));
+      EXPECT_EQ(0, WEXITSTATUS(status));
+    }
+  });
+
+  // Must come after children, as the FDs must be closed before the children
+  // will exit.
+  std::vector<FileDescriptor> read_fds;
+  std::vector<FileDescriptor> write_fds;
+
+  for (int i = 0; i < num_processes; i++) {
+    int fds[2];
+    ASSERT_THAT(pipe(fds), SyscallSucceeds());
+    read_fds.emplace_back(fds[0]);
+    write_fds.emplace_back(fds[1]);
+  }
+
+  // This process is one of the processes in the loop. It will be considered
+  // index 0.
+  for (int i = 1; i < num_processes; i++) {
+    // Read from current pipe index, write to next.
+    const int read_index = i;
+    const int read_fd = read_fds[read_index].get();
+
+    const int write_index = (i + 1) % num_processes;
+    const int write_fd = write_fds[write_index].get();
+
+    // std::vector isn't safe to use from the fork child.
+    FileDescriptor* read_array = read_fds.data();
+    FileDescriptor* write_array = write_fds.data();
+
+    pid_t child = fork();
+    if (!child) {
+      // Close all other FDs.
+      for (int j = 0; j < num_processes; j++) {
+        if (j != read_index) {
+          read_array[j].reset();
+        }
+        if (j != write_index) {
+          write_array[j].reset();
+        }
+      }
+
+      SwitchChild(read_fd, write_fd);
+      _exit(0);
+    }
+    ASSERT_THAT(child, SyscallSucceeds());
+    children.push_back(child);
+  }
+
+  // Read from current pipe index (0), write to next (1).
+  const int read_index = 0;
+  const int read_fd = read_fds[read_index].get();
+
+  const int write_index = 1;
+  const int write_fd = write_fds[write_index].get();
+
+  // Kick start the loop.
+  char buf = 'a';
+  ASSERT_THAT(WriteFd(write_fd, &buf, 1), SyscallSucceedsWithValue(1));
+
+  for (auto _ : state) {
+    ASSERT_THAT(ReadFd(read_fd, &buf, 1), SyscallSucceedsWithValue(1));
+    ASSERT_THAT(WriteFd(write_fd, &buf, 1), SyscallSucceedsWithValue(1));
+  }
+}
+
+BENCHMARK(BM_ProcessSwitch)->Range(2, 16)->UseRealTime();
+
+// Equivalent to BM_ThreadSwitch using threads instead of processes.
+void BM_ThreadSwitch(benchmark::State& state) {
+  // Code below assumes there are at least two threads.
+  const int num_threads = state.range(0);
+  ASSERT_GE(num_threads, 2);
+
+  // Must come after threads, as the FDs must be closed before the children
+  // will exit.
+  std::vector<std::unique_ptr<ScopedThread>> threads;
+  std::vector<FileDescriptor> read_fds;
+  std::vector<FileDescriptor> write_fds;
+
+  for (int i = 0; i < num_threads; i++) {
+    int fds[2];
+    ASSERT_THAT(pipe(fds), SyscallSucceeds());
+    read_fds.emplace_back(fds[0]);
+    write_fds.emplace_back(fds[1]);
+  }
+
+  // This thread is one of the threads in the loop. It will be considered
+  // index 0.
+  for (int i = 1; i < num_threads; i++) {
+    // Read from current pipe index, write to next.
+    //
+    // Transfer ownership of the FDs to the thread.
+    const int read_index = i;
+    const int read_fd = read_fds[read_index].release();
+
+    const int write_index = (i + 1) % num_threads;
+    const int write_fd = write_fds[write_index].release();
+
+    threads.emplace_back(std::make_unique<ScopedThread>([read_fd, write_fd] {
+      FileDescriptor read(read_fd);
+      FileDescriptor write(write_fd);
+      SwitchChild(read.get(), write.get());
+    }));
+  }
+
+  // Read from current pipe index (0), write to next (1).
+  const int read_index = 0;
+  const int read_fd = read_fds[read_index].get();
+
+  const int write_index = 1;
+  const int write_fd = write_fds[write_index].get();
+
+  // Kick start the loop.
+  char buf = 'a';
+  ASSERT_THAT(WriteFd(write_fd, &buf, 1), SyscallSucceedsWithValue(1));
+
+  for (auto _ : state) {
+    ASSERT_THAT(ReadFd(read_fd, &buf, 1), SyscallSucceedsWithValue(1));
+    ASSERT_THAT(WriteFd(write_fd, &buf, 1), SyscallSucceedsWithValue(1));
+  }
+
+  // The two FDs still owned by this thread are closed, causing the next thread
+  // to exit its loop and close its FDs, and so on until all threads exit.
+}
+
+BENCHMARK(BM_ThreadSwitch)->Range(2, 16)->UseRealTime();
+
+void BM_ThreadStart(benchmark::State& state) {
+  const int num_threads = state.range(0);
+
+  for (auto _ : state) {
+    state.PauseTiming();
+
+    auto barrier = new absl::Barrier(num_threads + 1);
+    std::vector<std::unique_ptr<ScopedThread>> threads;
+
+    state.ResumeTiming();
+
+    for (size_t i = 0; i < num_threads; ++i) {
+      threads.emplace_back(std::make_unique<ScopedThread>([barrier] {
+        if (barrier->Block()) {
+          delete barrier;
+        }
+      }));
+    }
+
+    if (barrier->Block()) {
+      delete barrier;
+    }
+
+    state.PauseTiming();
+
+    for (const auto& thread : threads) {
+      thread->Join();
+    }
+
+    state.ResumeTiming();
+  }
+}
+
+BENCHMARK(BM_ThreadStart)->Range(1, 2048)->UseRealTime();
+
+// Benchmark the complete fork + exit + wait.
+void BM_ProcessLifecycle(benchmark::State& state) {
+  const int num_procs = state.range(0);
+
+  std::vector<pid_t> pids(num_procs);
+  for (auto _ : state) {
+    for (size_t i = 0; i < num_procs; ++i) {
+      int pid = fork();
+      if (pid == 0) {
+        _exit(0);
+      }
+      ASSERT_THAT(pid, SyscallSucceeds());
+      pids[i] = pid;
+    }
+
+    for (const int pid : pids) {
+      ASSERT_THAT(RetryEINTR(waitpid)(pid, nullptr, 0),
+                  SyscallSucceedsWithValue(pid));
+    }
+  }
+}
+
+BENCHMARK(BM_ProcessLifecycle)->Range(1, 512)->UseRealTime();
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor