From 07b9077bfdcc14d27dd29b378d4fdf7914ebd28c Mon Sep 17 00:00:00 2001
From: Ghanan Gowripalan <ghanan@google.com>
Date: Fri, 6 Oct 2023 13:01:43 -0700
Subject: [PATCH] Introduce poll_benchmark

This benchmark performs similar measurements as epoll_benchmark.

PiperOrigin-RevId: 571414062
---
 test/perf/BUILD                    |  7 ++-
 test/perf/linux/BUILD              | 21 +++++++-
 test/perf/linux/epoll_benchmark.cc | 22 ++------
 test/perf/linux/poll_benchmark.cc  | 80 ++++++++++++++++++++++++++++++
 4 files changed, 110 insertions(+), 20 deletions(-)
 create mode 100644 test/perf/linux/poll_benchmark.cc

diff --git a/test/perf/BUILD b/test/perf/BUILD
index 3c5bb3e4e..dff5241b5 100644
--- a/test/perf/BUILD
+++ b/test/perf/BUILD
@@ -1,5 +1,5 @@
-load("//tools:defs.bzl", "more_shards")
 load("//test/runner:defs.bzl", "syscall_test")
+load("//tools:defs.bzl", "more_shards")
 
 package(
     default_applicable_licenses = ["//:license"],
@@ -26,6 +26,11 @@ syscall_test(
     test = "//test/perf/linux:epoll_benchmark",
 )
 
+syscall_test(
+    debug = False,
+    test = "//test/perf/linux:poll_benchmark",
+)
+
 syscall_test(
     size = "large",
     debug = False,
diff --git a/test/perf/linux/BUILD b/test/perf/linux/BUILD
index bf7545cb8..1a7d1f062 100644
--- a/test/perf/linux/BUILD
+++ b/test/perf/linux/BUILD
@@ -260,10 +260,29 @@ cc_binary(
         gbenchmark,
         gtest,
         "//test/util:epoll_util",
+        "//test/util:eventfd_util",
         "//test/util:file_descriptor",
+        "//test/util:posix_error",
+        "//test/util:test_main",
+        "//test/util:test_util",
+        "@com_google_absl//absl/time",
+    ],
+)
+
+cc_binary(
+    name = "poll_benchmark",
+    testonly = 1,
+    srcs = [
+        "poll_benchmark.cc",
+    ],
+    deps = [
+        gbenchmark,
+        gtest,
+        "//test/util:eventfd_util",
+        "//test/util:file_descriptor",
+        "//test/util:posix_error",
         "//test/util:test_main",
         "//test/util:test_util",
-        "//test/util:thread_util",
         "@com_google_absl//absl/time",
     ],
 )
diff --git a/test/perf/linux/epoll_benchmark.cc b/test/perf/linux/epoll_benchmark.cc
index 0b121338a..d4d5fa1c3 100644
--- a/test/perf/linux/epoll_benchmark.cc
+++ b/test/perf/linux/epoll_benchmark.cc
@@ -13,38 +13,24 @@
 // limitations under the License.
 
 #include <sys/epoll.h>
-#include <sys/eventfd.h>
 
-#include <atomic>
-#include <cerrno>
 #include <cstdint>
-#include <cstdlib>
-#include <ctime>
-#include <memory>
+#include <vector>
 
+#include "gmock/gmock.h"
 #include "gtest/gtest.h"
-#include "absl/time/time.h"
 #include "benchmark/benchmark.h"
 #include "test/util/epoll_util.h"
+#include "test/util/eventfd_util.h"
 #include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
 #include "test/util/test_util.h"
-#include "test/util/thread_util.h"
 
 namespace gvisor {
 namespace testing {
 
 namespace {
 
-// Returns a new eventfd.
-PosixErrorOr<FileDescriptor> NewEventFD() {
-  int fd = eventfd(0, /* flags = */ 0);
-  MaybeSave();
-  if (fd < 0) {
-    return PosixError(errno, "eventfd");
-  }
-  return FileDescriptor(fd);
-}
-
 // Also stolen from epoll.cc unit tests.
 void BM_EpollTimeout(benchmark::State& state) {
   constexpr int kFDsPerEpoll = 3;
diff --git a/test/perf/linux/poll_benchmark.cc b/test/perf/linux/poll_benchmark.cc
new file mode 100644
index 000000000..0eec232b4
--- /dev/null
+++ b/test/perf/linux/poll_benchmark.cc
@@ -0,0 +1,80 @@
+// Copyright 2023 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 <sys/poll.h>
+
+#include <cstdint>
+#include <utility>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "benchmark/benchmark.h"
+#include "test/util/eventfd_util.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+void Setup(int count, std::vector<FileDescriptor>& event_fds,
+           std::vector<pollfd>& poll_fds) {
+  for (int i = 0; i < count; ++i) {
+    FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD());
+    poll_fds.push_back(pollfd{.fd = fd.get(), .events = POLLIN});
+    event_fds.push_back(std::move(fd));
+  }
+}
+
+void BM_PollTimeout(benchmark::State& state) {
+  constexpr int kFDsPerPoll = 3;
+  std::vector<FileDescriptor> event_fds;
+  std::vector<pollfd> poll_fds;
+  ASSERT_NO_FATAL_FAILURE(Setup(kFDsPerPoll, event_fds, poll_fds));
+
+  const int timeout_ms = state.range(0);
+  for (auto _ : state) {
+    EXPECT_EQ(poll(poll_fds.data(), poll_fds.size(), timeout_ms), 0);
+  }
+}
+
+BENCHMARK(BM_PollTimeout)->Range(/*start=*/0, /*limit=*/8);
+
+void BM_PollAllEvents(benchmark::State& state) {
+  const int fds_per_poll = state.range(0);
+  std::vector<FileDescriptor> event_fds;
+  std::vector<pollfd> poll_fds;
+  ASSERT_NO_FATAL_FAILURE(Setup(fds_per_poll, event_fds, poll_fds));
+
+  constexpr uint64_t kEventVal = 5;
+  for (const auto& eventfd : event_fds) {
+    ASSERT_THAT(WriteFd(eventfd.get(), &kEventVal, sizeof(kEventVal)),
+                SyscallSucceedsWithValue(sizeof(kEventVal)));
+  }
+
+  constexpr int kTimeoutMs = 0;
+  for (auto _ : state) {
+    EXPECT_EQ(poll(poll_fds.data(), poll_fds.size(), kTimeoutMs), fds_per_poll);
+  }
+}
+
+BENCHMARK(BM_PollAllEvents)->Range(/*start=*/2, /*limit=*/1024);
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor