Add granular file tracing.

base/files/file_posix.cc

Index: base/files/file_posix.cc
diff --git a/base/files/file_posix.cc b/base/files/file_posix.cc
index 4c790571e8d6aeb732c6abfa038e51a7191edaa1..43119deeda0ae9e1bdbb947a970d9af82adc2db9 100644
--- a/base/files/file_posix.cc
+++ b/base/files/file_posix.cc
@@ -15,6 +15,7 @@
 #include "base/posix/eintr_wrapper.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/trace_event/trace_event.h"
 
 #if defined(OS_ANDROID)
 #include "base/os_compat_android.h"
@@ -174,12 +175,14 @@ void File::Close() {
     return;
 
   ThreadRestrictions::AssertIOAllowed();
+  TRACE_EVENT1(kTraceGroup, "Close", "path", path_.AsUTF8Unsafe());
   file_.reset();
 }
 
 int64 File::Seek(Whence whence, int64 offset) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
+  TRACE_EVENT1(kTraceGroup, "Seek", "path", path_.AsUTF8Unsafe())
 
 #if defined(OS_ANDROID)
   COMPILE_ASSERT(sizeof(int64) == sizeof(off64_t), off64_t_64_bit);
@@ -198,6 +201,8 @@ int File::Read(int64 offset, char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "Read", "path", path_.AsUTF8Unsafe(), "size", size);

[groby-ooo-7-16, 2015/04/28 20:26:55]

Given that you call this every read/seek/etc, might be worth storing the UTF8
path name.

[Dan Beam, 2015/04/29 02:48:03]

this is only called while tracing (in which case all of chrome is equally
slower)

+
   int bytes_read = 0;
   int rv;
   do {
@@ -218,6 +223,9 @@ int File::ReadAtCurrentPos(char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "ReadAtCurrentPost", "path", path_.AsUTF8Unsafe(),
+               "size", size);
+
   int bytes_read = 0;
   int rv;
   do {
@@ -234,7 +242,8 @@ int File::ReadAtCurrentPos(char* data, int size) {
 int File::ReadNoBestEffort(int64 offset, char* data, int size) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
-
+  TRACE_EVENT2(kTraceGroup, "ReadNoBestEffort", "path", path_.AsUTF8Unsafe(),
+               "size", size);
   return HANDLE_EINTR(pread(file_.get(), data, size, offset));
 }
 
@@ -244,6 +253,8 @@ int File::ReadAtCurrentPosNoBestEffort(char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "ReadAtCurrentPosNoBestEffort",
+               "path", path_.AsUTF8Unsafe(), "size", size);
   return HANDLE_EINTR(read(file_.get(), data, size));
 }
 
@@ -257,6 +268,9 @@ int File::Write(int64 offset, const char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "Write", "path", path_.AsUTF8Unsafe(),
+               "size", size);
+
   int bytes_written = 0;
   int rv;
   do {
@@ -277,6 +291,9 @@ int File::WriteAtCurrentPos(const char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "WriteAtCurrentPos", "path", path_.AsUTF8Unsafe(),
+               "size", size);
+
   int bytes_written = 0;
   int rv;
   do {
@@ -297,12 +314,16 @@ int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {
   if (size < 0)
     return -1;
 
+  TRACE_EVENT2(kTraceGroup, "WriteAtCurrentPosNoBestEffort",
+               "path", path_.AsUTF8Unsafe(), "size", size);
   return HANDLE_EINTR(write(file_.get(), data, size));
 }
 
 int64 File::GetLength() {
   DCHECK(IsValid());
 
+  TRACE_EVENT1(kTraceGroup, "GetLength", "path", path_.AsUTF8Unsafe())
+
   stat_wrapper_t file_info;
   if (CallFstat(file_.get(), &file_info))
     return false;
@@ -313,6 +334,10 @@ int64 File::GetLength() {
 bool File::SetLength(int64 length) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
+
+  TRACE_EVENT2(kTraceGroup, "SetLength", "path", path_.AsUTF8Unsafe(),
+               "length", length);
+
   return !CallFtruncate(file_.get(), length);
 }
 
@@ -320,6 +345,8 @@ bool File::SetTimes(Time last_access_time, Time last_modified_time) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
 
+  TRACE_EVENT1(kTraceGroup, "SetTimes", "path", path_.AsUTF8Unsafe())
+
   timeval times[2];
   times[0] = last_access_time.ToTimeVal();
   times[1] = last_modified_time.ToTimeVal();
@@ -330,6 +357,8 @@ bool File::SetTimes(Time last_access_time, Time last_modified_time) {
 bool File::GetInfo(Info* info) {
   DCHECK(IsValid());
 
+  TRACE_EVENT1(kTraceGroup, "GetInfo", "path", path_.AsUTF8Unsafe())
+
   stat_wrapper_t file_info;
   if (CallFstat(file_.get(), &file_info))
     return false;
@@ -339,10 +368,12 @@ bool File::GetInfo(Info* info) {
 }
 
 File::Error File::Lock() {
+  TRACE_EVENT1(kTraceGroup, "Lock", "path", path_.AsUTF8Unsafe())
   return CallFctnlFlock(file_.get(), true);
 }
 
 File::Error File::Unlock() {
+  TRACE_EVENT1(kTraceGroup, "Unlock", "path", path_.AsUTF8Unsafe())
   return CallFctnlFlock(file_.get(), false);
 }
 
@@ -350,6 +381,8 @@ File File::Duplicate() {
   if (!IsValid())
     return File();
 
+  TRACE_EVENT1(kTraceGroup, "Duplicate", "path", path_.AsUTF8Unsafe())
+
   PlatformFile other_fd = dup(GetPlatformFile());
   if (other_fd == -1)
     return File(OSErrorToFileError(errno));
@@ -442,10 +475,12 @@ void File::MemoryCheckingScopedFD::UpdateChecksum() {
 // NaCl doesn't implement system calls to open files directly.
 #if !defined(OS_NACL)
 // TODO(erikkay): does it make sense to support FLAG_EXCLUSIVE_* here?
-void File::DoInitialize(const FilePath& name, uint32 flags) {
+void File::DoInitialize(uint32 flags) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(!IsValid());
 
+  TRACE_EVENT1(kTraceGroup, "Initialize", "path", path_.AsUTF8Unsafe())
+
   int open_flags = 0;
   if (flags & FLAG_CREATE)
     open_flags = O_CREAT | O_EXCL;
@@ -497,7 +532,7 @@ void File::DoInitialize(const FilePath& name, uint32 flags) {
   mode |= S_IRGRP | S_IROTH;
 #endif
 
-  int descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
+  int descriptor = HANDLE_EINTR(open(path_.value().c_str(), open_flags, mode));
 
   if (flags & FLAG_OPEN_ALWAYS) {
     if (descriptor < 0) {
@@ -505,7 +540,7 @@ void File::DoInitialize(const FilePath& name, uint32 flags) {
       if (flags & FLAG_EXCLUSIVE_READ || flags & FLAG_EXCLUSIVE_WRITE)
         open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
 
-      descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
+      descriptor = HANDLE_EINTR(open(path_.value().c_str(), open_flags, mode));
       if (descriptor >= 0)
         created_ = true;
     }
@@ -520,7 +555,7 @@ void File::DoInitialize(const FilePath& name, uint32 flags) {
     created_ = true;
 
   if (flags & FLAG_DELETE_ON_CLOSE)
-    unlink(name.value().c_str());
+    unlink(path_.value().c_str());
 
   async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);
   error_details_ = FILE_OK;
@@ -531,14 +566,18 @@ void File::DoInitialize(const FilePath& name, uint32 flags) {
 bool File::DoFlush() {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
+
 #if defined(OS_NACL)
   NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
   return true;
-#elif defined(OS_LINUX) || defined(OS_ANDROID)
+#else
+  TRACE_EVENT1(kTraceGroup, "Flush", "path", path_.AsUTF8Unsafe())
+#if defined(OS_LINUX) || defined(OS_ANDROID)
   return !HANDLE_EINTR(fdatasync(file_.get()));
 #else
   return !HANDLE_EINTR(fsync(file_.get()));
-#endif
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+#endif  // defined(OS_NACL)
 }
 
 void File::SetPlatformFile(PlatformFile file) {