It's a long-dead platform, and we don't have any way to build for, test, or
maintain it, so there's no sense in doing acrobatics to support it.
If you need Windows CE support, use SDL 1.2. If you need Windows Phone support,
send SDL 2.0 patches for the newer Windows Mobile platform.
Implemented thread priority as the 'nice' value on Linux. High priority threads require root permissions (you shouldn't give your game root permissions though!)
Patrick Baggett 2011-02-16 22:58:33 PST
This enhancement is for both x86/x64 Windows.
The SDL implementation of mutexes uses the Win32 API interprocess
synchronization primitive called a "Mutex". This implementation is subpar
because it has a much higher overhead than an intraprocess mutex. The exact
technical details are below, but my tests have shown that for reasonably high
contention (10 threads on 4 physical cores), it has 13x higher overhead than
the Win32 CriticalSection API.
If this enhancement is accepted, I will write a patch to implement SDL mutexes
using the critical section API, which should dramatically reduce overhead and
improve scalability.
-- Tech details --
Normally, Win32 Mutexes are used across process boundaries to synchronize
separate processes. In order to lock or unlock them, a user->kernel space
transition is necessary, even in the uncontented case on a single CPU machine.
Win32 CriticalSection objects can only be used within the same process virtual
address space and thus to lock one, does not require a user->kernel space
transition for the uncontended case, and additionally may spin a short while
before going into kernel wait. This small spin allows a thread to obtain the
lock if the mutex is released shortly after the thread starts spinning, in
effect bypassing the overhead of user->kernel space transition which has higher
overhead than the spinning itself.
the pthread implementation of SDL_SemWaitTimeout() uses busy waiting, while
pthread's sem_timedwait() does work. Attached are patches that make use of it
Ozkan Sezer 2010-02-06 12:31:06 PST
Hi:
Here are some small fixes for compiling SDL against mingw-w64.
(see http://mingw-w64.sourceforge.net/ . Despite the name, it
supports both win32 and win64.)
src/audio/windx5/directx.h and src/video/windx5/directx.h (both
SDL-1.2 and SDL-1.3.) I get compilation errors about some union
not having a member named u1 and alike, because of other system
headers being included before this one and them already defining
DUMMYUNIONNAME and stuff. This header probably assumes that those
stuff are defined in windef.h, but mingw-w64 headers define them
in _mingw.h. Easily fixed by moving NONAMELESSUNION definition to
the top of the file.
src/thread/win32/SDL_systhread.c (both SDL-1.2 and SDL-1.3.) :
The __GNUC__ case for pfnSDL_CurrentBeginThread is 32-bit centric
because _beginthreadex returns uintptr_t, not unsigned long which
is 32 bits in win64. Changing the return type to uintptr_t fixes
it.
video/SDL_blit.h (and configure.in) (SDL-1.3-only) : MinGW-w64
uses msvcrt version of _aligned_malloc and _aligned_free and
they are defined in intrin.h (similar to VC). Adding proper
ifdefs fixes it. (Notes about macros to check: __MINGW32__ is
defined for both mingw.org and for mingw-w64 for both win32 and
win64, __MINGW64__ is only defined for _WIN64, so __MINGW64__
can't be used to detect mingw-w64: including _mingw.h and then
checking for __MINGW64_VERSION_MAJOR does the trick.)
SDL_win32video.h (SDL-1.3-only) : Tweaked the VINWER definition
and location in order to avoid multiple redefinition warnings.
Hope these are useful. Thanks.
