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(svn r17776) -Codechange: [SDL] make "update the video card"-process asynchronious. Profiling with gprof etc. hasn't shown us that DrawSurfaceToScreen takes a significant amount of CPU; only using TIC/TOC it became apparant that it was a heavy CPU-cycle user or that it was waiting for something.

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The benefit of making this function asynchronious ranges from 2%-25% (real time) during fast forward on dual core/hyperthreading-enabled CPUs; 8bpp improvements are, in my test cases, significantly smaller than 32bpp improvements.
On single core non-hyperthreading-enabled CPUs the extra locking/scheduling costs up to 1% extra realtime in fast forward. You can use -v sdl:no_threads to disable threading and undo this loss.
During normal non-fast-forwarded games the benefit/costs are negligable except when the gameloop takes more than about 90% of the time of a tick.
Note that allegro's performance does not improve with this system, likely due to their way of getting data to the video card. It is not implemented for the OS X/Windows video backends, unless (ofcourse) SDL is used there.
Funny is that the performance of the 32bpp(-anim) blitter is, at least in some test cases, significantly faster (more than 10%) than the 8bpp(-optimized) blitter when looking at real time in fast forward on a dual core CPU; it was slower.
The idea comes from a paper/report by Idar Borlaug and Knut Imar Hagen.
This commit is contained in:
rubidium
2009-10-15 17:41:06 +00:00
parent db7c91b647
commit 0307d13d0a
6 changed files with 132 additions and 8 deletions
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15
src/thread/thread_win32.cpp
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@@ -107,16 +107,19 @@ private:
class ThreadMutex_Win32 : public ThreadMutex {
private:
CRITICAL_SECTION critical_section;
HANDLE event;
public:
ThreadMutex_Win32()
{
InitializeCriticalSection(&this->critical_section);
this->event = CreateEvent(NULL, FALSE, FALSE, NULL);
}
/* virtual */ ~ThreadMutex_Win32()
{
DeleteCriticalSection(&this->critical_section);
CloseHandle(this->event);
}
/* virtual */ void BeginCritical()
@@ -128,6 +131,18 @@ public:
{
LeaveCriticalSection(&this->critical_section);
}
/* virtual */ void WaitForSignal()
{
this->EndCritical();
WaitForSingleObject(this->event, INFINITE);
this->BeginCritical();
}
/* virtual */ void SendSignal()
{
SetEvent(this->event);
}
};
/* static */ ThreadMutex *ThreadMutex::New()