Shared Raster Worker Threads

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
old mode 100644
new mode 100755
index be4a2c55adfbcb22214a0a92439f59da8fd112e2..ac0982244e1e4f12d28d61635fee9f1d1b0c921a
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -5,6 +5,7 @@
 #include "cc/base/switches.h"
 
 #include "base/command_line.h"
+#include "base/strings/string_number_conversions.h"
 
 namespace cc {
 namespace switches {
@@ -198,5 +199,16 @@ bool IsMapImageEnabled() {
   return false;
 }
 
+int GetNumRasterThreads() {

[reveman, 2013/11/21 16:36:10]

nit: indent 2 spaces not 4

[reveman, 2013/11/21 16:36:10]

return size_t instead of int?

+    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+    std::string string_value =
+        command_line.GetSwitchValueASCII(cc::switches::kNumRasterThreads);

[vivekg, 2013/11/21 17:18:12]

In case kNumRasterThreads command line switch is not provided, the string_value
would be empty. We can bailout early by using std::string::empty() and returning
the minimum  number i.e. 1.

[reveman, 2013/11/21 17:30:02]

Yes, please add a command_line.HasSwitch check and a kDefaultNumRasterThreads
constant that is returned when switch is not present.

+    int num_threads;
+    base::StringToInt(string_value, &num_threads);
+    if (num_threads == 0)
+        num_threads = 1;  // Min num of threads

[reveman, 2013/11/21 16:36:10]

we should also put a limit on the max number of threads. maybe you could do
something like this:

const int kMinRasterThreads = 1;
const int kMaxRasterThreads = 64;
return std::max(kMinRasterThreads, std::min(num_threads, kMaxRasterThreads));

+    return num_threads;
+}
+
 }  // namespace switches
 }  // namespace cc