Record Chrome trace events in tcmalloc heap profiles

chrome/browser/chrome_browser_main_linux.cc

Index: chrome/browser/chrome_browser_main_linux.cc
diff --git a/chrome/browser/chrome_browser_main_linux.cc b/chrome/browser/chrome_browser_main_linux.cc
index 870a95c53670669280fffd38d6492facb7d74dff..355401e83a7bedf84c1dccf3cac7cfe5b78d93f0 100644
--- a/chrome/browser/chrome_browser_main_linux.cc
+++ b/chrome/browser/chrome_browser_main_linux.cc
@@ -4,6 +4,8 @@
 
 #include "chrome/browser/chrome_browser_main_linux.h"
 
+#include "base/debug/trace_memory.h"
+
 #if !defined(OS_CHROMEOS)
 #include "chrome/browser/storage_monitor/storage_monitor_linux.h"
 #include "content/public/browser/browser_thread.h"
@@ -101,6 +103,58 @@ bool IsCrashReportingEnabled(const PrefService* local_state) {
 }
 #endif  // defined(USE_LINUX_BREAKPAD)
 
+/*
+ * std::string my_str;
+    TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
+      "cc::Picture", clone.get(), my_str);
+
+std::string* my_str;
+tcmalloc_dump(&my_str);
+MyStringOnwer : base::Debug::ConvdrtableToTraceLog // cc/debug/traced_picture.h for example
+scoped_ptr<MyStringOwner> mystr = ...;
+
+
+TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID("tcmalloc", "tcmalloc::Heap", 1, my_str);
+*/
+class MemoryDumpHolder : public base::debug::ConvertableToTraceFormat {
+ public:
+  // Takes ownership of dump, which must be allocated with malloc() and NULL
+  // terminated.
+  explicit MemoryDumpHolder(char* dump) : dump_(dump) {}
+  virtual ~MemoryDumpHolder() { free(dump_); }
+
+  // base::debug::ConvertableToTraceFormat overrides:
+  virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
+    out->append("{\"heap_dump\": ");
+    //TODO - use JSON version
+    out->append(dump_);
+    LOG(ERROR) << "JAMESDEBUG1\n" << dump_;
+    out->append("\"}");
+  }
+
+ private:
+  char* dump_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryDumpHolder);
+};
+
+void DumpMemoryProfile() {
+  // Check to see if tracing is enabled for the memory category.
+  bool enabled = TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED("tcmalloc2");

[nduca, 2013/05/20 23:03:41]

static bool* enabled = ...
if (*enabled) {

}

[dsinclair, 2013/05/21 00:32:07]

bool enabled;
TRACE_EVENT_CATEGORY_GROUP_ENABLED("tcmalloc2", &enabled);
if (enabled) {
}
would also work.

+  if (enabled) {
+    // We take ownership of this string.
+    char* dump = base::TraceMemoryDumpAsString();
+//    LOG(ERROR) << "JAMESDEBUG2\n" << dump;
+    scoped_ptr<MemoryDumpHolder> dump_holder(new MemoryDumpHolder(dump));

[nduca, 2013/05/20 23:04:44]

maybe this needs to be scoped_ptr<base::debug::ConvertableToTraceFormat>
dump_holder()

[dsinclair, 2013/05/21 00:32:07]

Doesn't have to be, you can use PassAs below.

+//    const int kSnapshotId = 1;
+    TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
+        "tcmalloc2", "tcmalloc2::Heap", dump_holder.get(), dump_holder);

[nduca, 2013/05/20 23:03:41]

3rd arg should be 1

[dsinclair, 2013/05/21 00:32:07]

You don't want to do the .get() on dump_holder. That will return the
MemoryDumpHolder* which will get interpreted by trace event as the raw pointer
type and print the address.

You want to do: 

dump_holder.PassAs<base::debug::ConvertableToTraceFormat>()

which will provide a scoped_ptr<ConvertableToTraceFormat> to trace event and
call the AppendAsTraceFormat correctly.

Is there some way we could detect this in trace event? Figure out that the
pointer type you passed inherits from Convertable and print a warning?

+  }
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+                                          base::Bind(&DumpMemoryProfile),
+                                          base::TimeDelta::FromSeconds(10));
+}
+
 }  // namespace
 
 ChromeBrowserMainPartsLinux::ChromeBrowserMainPartsLinux(
@@ -141,6 +195,19 @@ void ChromeBrowserMainPartsLinux::PostProfileInit() {
   ChromeBrowserMainPartsPosix::PostProfileInit();
 }
 
+void ChromeBrowserMainPartsLinux::PreMainMessageLoopRun() {
+  ChromeBrowserMainPartsPosix::PreMainMessageLoopRun();
+
+  // TODO(jamescook): This could be moved earlier in startup to capture more
+  // startup allocations.
+  base::TraceMemoryStart();
+
+  // Dump a heap profile every 10 seconds, forever.
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+                                          base::Bind(&DumpMemoryProfile),
+                                          base::TimeDelta::FromSeconds(10));
+}
+
 void ChromeBrowserMainPartsLinux::PostMainMessageLoopRun() {
 #if !defined(OS_CHROMEOS)
   // Delete it now. Otherwise the FILE thread would be gone when we try to
@@ -149,5 +216,8 @@ void ChromeBrowserMainPartsLinux::PostMainMessageLoopRun() {
   storage_monitor_.reset();
 #endif
 
+  base::TraceMemoryDump();
+  base::TraceMemoryStop();
+
   ChromeBrowserMainPartsPosix::PostMainMessageLoopRun();
 }