From 1771cbf43d9a1334e3d870c635b4215bb888dd98 Mon Sep 17 00:00:00 2001 From: "digit@google.com" Date: Thu, 26 Jan 2012 21:26:40 +0000 Subject: posix: Avoid static initializers in static/global mutexes This patch removes static initializers related to static and global mutexes from the final library's machine code when building on a pthread-capable system. We use PTHREAD_MUTEX_INITIALIZER to perform POD-style initialization. You need a line like the following to declare a global mutex with it: SkBaseMutex gMutex = { PTHREAD_MUTEX_INITIALIZER }; We introduce the SK_DECLARE_STATIC_MUTEX and SK_DECLARE_GLOBAL_MUTEX macros to be able to declare static/global mutexes in the source tree uniformly. SkMutex is now defined as a sub-class of SkBaseMutex, with standard construction/destruction semantics. This is useful if the mutex object is a member of another C++ class, or allocated dynamically. We also modify a few places to refer to SkBaseMutex instead of a SkMutex, where it makes sense. Generally speaking, client code should hold and use pointers to SkBaseMutex whenever they can now. We defined a new built-time macro named SK_USE_POSIX_THREADS to indicate that we're using a pthread-based SkThread.h interface. The macro will also be used in future patches to implement other helper thread synchronization classes. Finally, we inline the acquire() and release() functions in the case of Posix to improve performance a bit. Running: 'bench -repeat 10 -match mutex' on an Android device or a 2.4GHz Xeon Linux desktop shows the following improvements: Before After Galaxy Nexus 1.64 1.45 Nexus S 1.47 1.16 Xoom 1.86 1.66 Xeon 0.36 0.31 This removes 5 static mutex initializers from the library Review URL: https://codereview.appspot.com/5501066 git-svn-id: http://skia.googlecode.com/svn/trunk@3091 2bbb7eff-a529-9590-31e7-b0007b416f81 --- gyp/common_conditions.gypi | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'gyp') diff --git a/gyp/common_conditions.gypi b/gyp/common_conditions.gypi index 99cabc9b16..faa48fb45d 100644 --- a/gyp/common_conditions.gypi +++ b/gyp/common_conditions.gypi @@ -205,6 +205,14 @@ }, ], + # We can POD-style initialization of static mutexes to avoid generating + # static initializers if we're using a pthread-compatible thread interface. + [ 'skia_os != "win"', { + 'defines': [ + 'SK_USE_POSIX_THREADS' + ], + }], + ], # end 'conditions' } -- cgit v1.2.3