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authorrubidium <rubidium@openttd.org>2009-10-15 17:41:06 +0000
committerrubidium <rubidium@openttd.org>2009-10-15 17:41:06 +0000
commitf4f4044859b9ae89f70dcffc459b81d769c0a93f (patch)
tree88f1b2f84ce673f3489d6fec18479fb2714da5c1
parent7f52cfe72bd6471395aa841c7814d2083c179d9f (diff)
downloadopenttd-f4f4044859b9ae89f70dcffc459b81d769c0a93f.tar.xz
(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.
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.
-rw-r--r--src/thread/thread.h13
-rw-r--r--src/thread/thread_none.cpp2
-rw-r--r--src/thread/thread_pthread.cpp18
-rw-r--r--src/thread/thread_win32.cpp15
-rw-r--r--src/video/allegro_v.cpp7
-rw-r--r--src/video/sdl_v.cpp85
6 files changed, 132 insertions, 8 deletions
diff --git a/src/thread/thread.h b/src/thread/thread.h
index 22873bee5..98c48d15d 100644
--- a/src/thread/thread.h
+++ b/src/thread/thread.h
@@ -68,6 +68,19 @@ public:
* End of the critical section
*/
virtual void EndCritical() = 0;
+
+ /**
+ * Wait for a signal to be send.
+ * @pre You must be in the critical section.
+ * @note While waiting the critical section is left.
+ * @post You will be in the critical section.
+ */
+ virtual void WaitForSignal() = 0;
+
+ /**
+ * Send a signal and wake the 'thread' that was waiting for it.
+ */
+ virtual void SendSignal() = 0;
};
#endif /* THREAD_H */
diff --git a/src/thread/thread_none.cpp b/src/thread/thread_none.cpp
index 861f2cfd6..67679bc81 100644
--- a/src/thread/thread_none.cpp
+++ b/src/thread/thread_none.cpp
@@ -23,6 +23,8 @@ class ThreadMutex_None : public ThreadMutex {
public:
virtual void BeginCritical() {}
virtual void EndCritical() {}
+ virtual void WaitForSignal() {}
+ virtual void SendSignal() {}
};
/* static */ ThreadMutex *ThreadMutex::New()
diff --git a/src/thread/thread_pthread.cpp b/src/thread/thread_pthread.cpp
index 483b71c0f..ca1fb8f5a 100644
--- a/src/thread/thread_pthread.cpp
+++ b/src/thread/thread_pthread.cpp
@@ -12,6 +12,7 @@
#include "../stdafx.h"
#include "thread.h"
#include <pthread.h>
+#include <errno.h>
/**
* POSIX pthread version for ThreadObject.
@@ -95,16 +96,21 @@ private:
class ThreadMutex_pthread : public ThreadMutex {
private:
pthread_mutex_t mutex;
+ pthread_cond_t condition;
public:
ThreadMutex_pthread()
{
pthread_mutex_init(&this->mutex, NULL);
+ pthread_cond_init(&this->condition, NULL);
}
/* virtual */ ~ThreadMutex_pthread()
{
- pthread_mutex_destroy(&this->mutex);
+ int err = pthread_cond_destroy(&this->condition);
+ assert(err != EBUSY);
+ err = pthread_mutex_destroy(&this->mutex);
+ assert(err != EBUSY);
}
/* virtual */ void BeginCritical()
@@ -116,6 +122,16 @@ public:
{
pthread_mutex_unlock(&this->mutex);
}
+
+ /* virtual */ void WaitForSignal()
+ {
+ pthread_cond_wait(&this->condition, &this->mutex);
+ }
+
+ /* virtual */ void SendSignal()
+ {
+ pthread_cond_signal(&this->condition);
+ }
};
/* static */ ThreadMutex *ThreadMutex::New()
diff --git a/src/thread/thread_win32.cpp b/src/thread/thread_win32.cpp
index e752de1ae..a3b2d3734 100644
--- a/src/thread/thread_win32.cpp
+++ b/src/thread/thread_win32.cpp
@@ -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()
diff --git a/src/video/allegro_v.cpp b/src/video/allegro_v.cpp
index e566a8dd5..a92a115e2 100644
--- a/src/video/allegro_v.cpp
+++ b/src/video/allegro_v.cpp
@@ -7,7 +7,12 @@
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
-/** @file allegro_v.cpp Implementation of the Allegro video driver. */
+/**
+ * @file allegro_v.cpp Implementation of the Allegro video driver.
+ * @note Implementing threaded pushing of data to the display is
+ * not faster (it's a few percent slower) in contrast to the
+ * results gained with threading it for SDL.
+ */
#ifdef WITH_ALLEGRO
diff --git a/src/video/sdl_v.cpp b/src/video/sdl_v.cpp
index a17c95ebd..1cb6d828b 100644
--- a/src/video/sdl_v.cpp
+++ b/src/video/sdl_v.cpp
@@ -20,6 +20,7 @@
#include "../blitter/factory.hpp"
#include "../network/network.h"
#include "../functions.h"
+#include "../thread/thread.h"
#include "sdl_v.h"
#include <SDL.h>
@@ -28,6 +29,15 @@ static FVideoDriver_SDL iFVideoDriver_SDL;
static SDL_Surface *_sdl_screen;
static bool _all_modes;
+/** Whether the drawing is/may be done in a separate thread. */
+static bool _draw_threaded;
+/** Thread used to 'draw' to the screen, i.e. push data to the screen. */
+static ThreadObject *_draw_thread = NULL;
+/** Mutex to keep the access to the shared memory controlled. */
+static ThreadMutex *_draw_mutex = NULL;
+/** Should we keep continue drawing? */
+static volatile bool _draw_continue;
+
#define MAX_DIRTY_RECTS 100
static SDL_Rect _dirty_rects[MAX_DIRTY_RECTS];
static int _num_dirty_rects;
@@ -99,6 +109,22 @@ static void DrawSurfaceToScreen()
}
}
+static void DrawSurfaceToScreenThread(void *)
+{
+ /* First wait till we 'may' start */
+ _draw_mutex->BeginCritical();
+ _draw_mutex->WaitForSignal();
+
+ while (_draw_continue) {
+ /* Then just draw and wait till we stop */
+ DrawSurfaceToScreen();
+ _draw_mutex->WaitForSignal();
+ }
+
+ _draw_mutex->EndCritical();
+ _draw_thread->Exit();
+}
+
static const Dimension _default_resolutions[] = {
{ 640, 480},
{ 800, 600},
@@ -214,6 +240,9 @@ static bool CreateMainSurface(uint w, uint h)
return false;
}
+ /* Delay drawing for this cycle; the next cycle will redraw the whole screen */
+ _num_dirty_rects = 0;
+
_screen.width = newscreen->w;
_screen.height = newscreen->h;
_screen.pitch = newscreen->pitch / (bpp / 8);
@@ -445,6 +474,9 @@ const char *VideoDriver_SDL::Start(const char * const *parm)
SDL_CALL SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY, SDL_DEFAULT_REPEAT_INTERVAL);
SDL_CALL SDL_EnableUNICODE(1);
+
+ _draw_threaded = GetDriverParam(parm, "no_threads") == NULL && GetDriverParam(parm, "no_thread") == NULL;
+
return NULL;
}
@@ -463,6 +495,25 @@ void VideoDriver_SDL::MainLoop()
int numkeys;
Uint8 *keys;
+ if (_draw_threaded) {
+ /* Initialise the mutex first, because that's the thing we *need*
+ * directly in the newly created thread. */
+ _draw_mutex = ThreadMutex::New();
+ if (_draw_mutex == NULL) {
+ _draw_threaded = false;
+ } else {
+ _draw_mutex->BeginCritical();
+ _draw_continue = true;
+
+ _draw_threaded = ThreadObject::New(&DrawSurfaceToScreenThread, NULL, &_draw_thread);
+ }
+
+ /* Free the mutex if we won't be able to use it. */
+ if (!_draw_threaded) delete _draw_mutex;
+ }
+
+ DEBUG(driver, 1, "SDL: using %sthreads", _draw_threaded ? "" : "no ");
+
for (;;) {
uint32 prev_cur_ticks = cur_ticks; // to check for wrapping
InteractiveRandom(); // randomness
@@ -505,23 +556,45 @@ void VideoDriver_SDL::MainLoop()
if (old_ctrl_pressed != _ctrl_pressed) HandleCtrlChanged();
+ /* The gameloop is the part that can run asynchroniously. The rest
+ * except sleeping can't. */
+ if (_draw_threaded) _draw_mutex->EndCritical();
+
GameLoop();
+ if (_draw_threaded) _draw_mutex->BeginCritical();
+
_screen.dst_ptr = _sdl_screen->pixels;
UpdateWindows();
if (++pal_tick > 4) {
CheckPaletteAnim();
pal_tick = 1;
}
- DrawSurfaceToScreen();
+
+ /* End of the critical part. */
+ if (_draw_threaded) {
+ _draw_mutex->SendSignal();
+ } else {
+ /* Oh, we didn't have threads, then just draw unthreaded */
+ DrawSurfaceToScreen();
+ }
} else {
- SDL_CALL SDL_Delay(1);
- _screen.dst_ptr = _sdl_screen->pixels;
- NetworkDrawChatMessage();
- DrawMouseCursor();
- DrawSurfaceToScreen();
+ /* Release the thread while sleeping */
+ if (_draw_threaded) _draw_mutex->EndCritical();
+ CSleep(1);
+ if (_draw_threaded) _draw_mutex->BeginCritical();
}
}
+
+ if (_draw_threaded) {
+ _draw_continue = false;
+ _draw_mutex->SendSignal();
+ _draw_mutex->EndCritical();
+ _draw_thread->Join();
+
+ delete _draw_mutex;
+ delete _draw_thread;
+ }
}
bool VideoDriver_SDL::ChangeResolution(int w, int h)