base: Move renderer threads to the appropriate cpuset.

base/threading/platform_thread_linux.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/threading/platform_thread.h"
 
 #include <errno.h>
 #include <sched.h>
 #include <stddef.h>
 
+#include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/threading/platform_thread_internal_posix.h"
 #include "base/threading/thread_id_name_manager.h"
 #include "base/tracked_objects.h"
 #include "build/build_config.h"
 
 #if !defined(OS_NACL)
 #include <pthread.h>
 #include <sys/prctl.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ skipping 35 matching lines @@
       maybe_realtime_prio.sched_priority == kRealTimePrio.sched_priority) {
     *priority = ThreadPriority::REALTIME_AUDIO;
     return true;
   }
 #endif
   return false;
 }
 
 }  // namespace internal
 
+namespace {
+#if !defined(OS_NACL)
+const FilePath::CharType kCpusetDirectory[] =
+    FILE_PATH_LITERAL("/sys/fs/cgroup/cpuset/chrome");

[Dmitry Torokhov, 2016/09/12 16:18:09]

I wonder if, instead of having static cpuset placement, we should not be reading
"/proc/self/cpuset" on startup and then append urgent/non-urgent to the starting
cpuset.

We should need to make sure we actually start chrome in proper cpuset first
though.

[reveman, 2016/09/16 22:16:11]

sgtm.

dtor, can you take care of starting chrome in the proper cpuset?

+#endif
+}  // namespace
+
 // static
 void PlatformThread::SetName(const std::string& name) {
   ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
   tracked_objects::ThreadData::InitializeThreadContext(name);
 
 #if !defined(OS_NACL)
   // On linux we can get the thread names to show up in the debugger by setting
   // the process name for the LWP.  We don't want to do this for the main
   // thread because that would rename the process, causing tools like killall
   // to stop working.
   if (PlatformThread::CurrentId() == getpid())
     return;
 
   // http://0pointer.de/blog/projects/name-your-threads.html
   // Set the name for the LWP (which gets truncated to 15 characters).
   // Note that glibc also has a 'pthread_setname_np' api, but it may not be
   // available everywhere and it's only benefit over using prctl directly is
   // that it can set the name of threads other than the current thread.
   int err = prctl(PR_SET_NAME, name.c_str());
   // We expect EPERM failures in sandboxed processes, just ignore those.
   if (err < 0 && errno != EPERM)
     DPLOG(ERROR) << "prctl(PR_SET_NAME)";
 #endif  //  !defined(OS_NACL)
 }
 
+#if !defined(OS_NACL)
+// static
+void PlatformThread::SetThreadAffinity(PlatformThreadId id,
+                                       ThreadPriority priority) {
+  // Move thread into the appropriate cpuset when chrome cpuset directory
+  // exists. Threads with BACKGROUND priority are move to the "non-urgent"
+  // cpuset and threads with DISPLAY and REALTIME_AUDIO priority are moved
+  // to "urgent" cpuset.
+  FilePath cpuset_filepath(kCpusetDirectory);
+  switch (priority) {
+    case ThreadPriority::NORMAL:
+      break;
+    case ThreadPriority::BACKGROUND:
+      cpuset_filepath = cpuset_filepath.Append(FILE_PATH_LITERAL("non-urgent"));
+      break;
+    case ThreadPriority::DISPLAY:
+    case ThreadPriority::REALTIME_AUDIO:
+      cpuset_filepath = cpuset_filepath.Append(FILE_PATH_LITERAL("urgent"));
+      break;
+  }
+  if (DirectoryExists(cpuset_filepath)) {
+    FilePath tasks_filepath =
+        cpuset_filepath.Append(FILE_PATH_LITERAL("tasks"));
+    std::string tid = IntToString(id);
+    int bytes_written = WriteFile(tasks_filepath, tid.c_str(), tid.size());
+    if (bytes_written != static_cast<int>(tid.size())) {
+      DVLOG(1) << "Failed to add " << tid << " to " << tasks_filepath.value();
+    }
+  }
+}
+#endif  //  !defined(OS_NACL)
+
 void InitThreading() {}
 
 void TerminateOnThread() {}
 
 size_t GetDefaultThreadStackSize(const pthread_attr_t& attributes) {
 #if !defined(THREAD_SANITIZER)
   return 0;
 #else
   // ThreadSanitizer bloats the stack heavily. Evidence has been that the
   // default stack size isn't enough for some browser tests.
   return 2 * (1 << 23);  // 2 times 8192K (the default stack size on Linux).
 #endif
 }
 
 }  // namespace base