Sync trace time on Chrome OS (just like Android)

base/debug/trace_event_impl.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/debug/trace_event_impl.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 665 matching lines @@
                                 const std::string& extra)
 {
 #if defined(OS_WIN)
   TraceEventETWProvider::Trace(name, phase, id, extra);
 #endif
   INTERNAL_TRACE_EVENT_ADD(phase, "ETW Trace Event", name,
                            TRACE_EVENT_FLAG_COPY, "id", id, "extra", extra);
 }
 
 void TraceLog::AddClockSyncMetadataEvents() {
-#if defined(OS_ANDROID)
+#if defined(OS_ANDROID) || defined(OS_CHROMEOS)
   // Since Android does not support sched_setaffinity, we cannot establish clock

[nduca, 2012/02/27 22:47:36]

You probably want to adjust the comments here, they're a bit stale.

[jar (doing other things), 2012/02/27 22:54:10]

+1
On 2012/02/27 22:47:36, nduca wrote:

   // sync unless the scheduler clock is set to global. If the trace_clock file
   // can't be read, we will assume the kernel doesn't support tracing and do
   // nothing.
   std::string clock_mode;
   if (!file_util::ReadFileToString(
           FilePath("/sys/kernel/debug/tracing/trace_clock"),
           &clock_mode))
     return;
 
   if (clock_mode != "local [global]\n") {
@@ skipping 58 matching lines @@
   // Create a FNV hash from the process ID for XORing.
   // See http://isthe.com/chongo/tech/comp/fnv/ for algorithm details.
   unsigned long long offset_basis = 14695981039346656037ull;
   unsigned long long fnv_prime = 1099511628211ull;
   unsigned long long pid = static_cast<unsigned long long>(process_id_);
   process_id_hash_ = (offset_basis ^ pid) * fnv_prime;
 }
 
 }  // namespace debug
 }  // namespace base