newnet: Make main thread block on second call to fpathDroidRoute. This makes the code more deterministic, improving synch a lot.
Also, merge most of fpath.c from Qt branch, fixes a useless delay before pathfinding starts and should reduce merge conflicts later.master
Cyp
parent
864b830a44
commit
6cdde8d607
125
src/fpath.c
125
src/fpath.c
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@ -24,6 +24,22 @@
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*
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*/
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// TODO Delete these defines during Qt merge.
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#define WZ_THREAD SDL_Thread
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#define WZ_MUTEX SDL_mutex
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#define WZ_SEMAPHORE SDL_sem
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#define wzMutexLock SDL_LockMutex
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#define wzMutexUnlock SDL_UnlockMutex
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#define wzSemaphoreCreate SDL_CreateSemaphore
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#define wzSemaphoreDestroy SDL_DestroySemaphore
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#define wzSemaphoreWait SDL_SemWait
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#define wzSemaphorePost SDL_SemPost
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#define wzThreadJoin(x) SDL_WaitThread(x, NULL)
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#define wzMutexDestroy SDL_DestroyMutex
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#define wzMutexCreate SDL_CreateMutex
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#define wzYieldCurrentThread() SDL_Delay(10)
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#define wzThreadCreate SDL_CreateThread
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#define wzThreadStart(x)
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#include <SDL.h>
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#include <SDL_thread.h>
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@ -75,11 +91,15 @@ static const Vector2i aDirOffset[NUM_DIR] =
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};
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// threading stuff
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static SDL_Thread *fpathThread = NULL;
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static SDL_sem *fpathSemaphore = NULL;
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static WZ_THREAD *fpathThread = NULL;
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static WZ_MUTEX *fpathMutex = NULL;
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static WZ_SEMAPHORE *fpathSemaphore = NULL;
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static PATHJOB *firstJob = NULL;
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static PATHRESULT *firstResult = NULL;
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static bool waitingForResult = false;
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static uint32_t waitingForResultId;
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static WZ_SEMAPHORE *waitingForResultSemaphore = NULL;
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static void fpathExecute(PATHJOB *psJob, PATHRESULT *psResult);
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@ -90,14 +110,14 @@ static int fpathJobQueueLength(void)
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PATHJOB *psJob;
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int count = 0;
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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psJob = firstJob;
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while (psJob)
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{
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count++;
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psJob = psJob->next;
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}
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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return count;
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}
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@ -108,7 +128,7 @@ static int fpathResultQueueLength(void)
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PATHRESULT *psResult;
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int count = 0;
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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psResult = firstResult;
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while (psResult)
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{
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@ -118,7 +138,7 @@ static int fpathResultQueueLength(void)
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}
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psResult = psResult->next;
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}
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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return count;
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}
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@ -126,7 +146,7 @@ static int fpathResultQueueLength(void)
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/** This runs in a separate thread */
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static int fpathThreadFunc(WZ_DECL_UNUSED void *data)
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{
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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while (!fpathQuit)
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{
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@ -148,9 +168,10 @@ static int fpathThreadFunc(WZ_DECL_UNUSED void *data)
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if (!gotWork)
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{
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SDL_SemPost(fpathSemaphore);
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SDL_Delay(100);
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SDL_SemWait(fpathSemaphore);
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ASSERT(!waitingForResult, "Waiting for a result (id %u) that doesn't exist.", waitingForResultId);
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wzMutexUnlock(fpathMutex);
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wzSemaphoreWait(fpathSemaphore); // Go to sleep until needed.
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wzMutexLock(fpathMutex);
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continue;
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}
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@ -166,14 +187,14 @@ static int fpathThreadFunc(WZ_DECL_UNUSED void *data)
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firstResult = psResult;
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psResult = NULL; // now hands off
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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// Execute path-finding for this job using our local temporaries
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memset(&result, 0, sizeof(result));
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result.sMove.asPath = NULL;
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fpathExecute(&job, &result);
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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// Find our result again, and replace it with our local temporary
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// We do it this way to avoid a race condition where a droid dies
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@ -189,8 +210,16 @@ static int fpathThreadFunc(WZ_DECL_UNUSED void *data)
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psResult->retval = result.retval;
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psResult->done = true;
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}
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// Unblock the main thread, if it was waiting for this particular result.
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if (waitingForResult && waitingForResultId == job.droidID)
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{
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waitingForResult = false;
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objTrace(waitingForResultId, "These are the droids you are looking for.");
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wzSemaphorePost(waitingForResultSemaphore);
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}
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SDL_SemPost(fpathSemaphore);
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}
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wzMutexUnlock(fpathMutex);
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return 0;
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}
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@ -203,8 +232,11 @@ BOOL fpathInitialise(void)
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if (!fpathThread)
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{
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fpathSemaphore = SDL_CreateSemaphore(1);
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fpathThread = SDL_CreateThread(fpathThreadFunc, NULL);
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fpathMutex = wzMutexCreate();
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fpathSemaphore = wzSemaphoreCreate(0);
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waitingForResultSemaphore = wzSemaphoreCreate(0);
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fpathThread = wzThreadCreate(fpathThreadFunc, NULL);
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wzThreadStart(fpathThread);
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}
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return true;
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@ -215,14 +247,19 @@ void fpathShutdown()
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{
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// Signal the path finding thread to quit
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fpathQuit = true;
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wzSemaphorePost(fpathSemaphore); // Wake up thread.
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fpathHardTableReset();
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if (fpathThread)
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{
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SDL_WaitThread(fpathThread, NULL);
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wzThreadJoin(fpathThread);
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fpathThread = NULL;
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SDL_DestroySemaphore(fpathSemaphore);
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wzMutexDestroy(fpathMutex);
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fpathMutex = NULL;
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wzSemaphoreDestroy(fpathSemaphore);
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fpathSemaphore = NULL;
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wzSemaphoreDestroy(waitingForResultSemaphore);
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waitingForResultSemaphore = NULL;
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}
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}
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@ -345,7 +382,7 @@ void fpathRemoveDroidData(int id)
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PATHRESULT *psResult;
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PATHRESULT *psPrevResult = NULL;
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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psJob = firstJob;
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psResult = firstResult;
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@ -398,7 +435,7 @@ void fpathRemoveDroidData(int id)
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psResult = psResult->next;
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}
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}
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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}
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@ -418,12 +455,12 @@ static FPATH_RETVAL fpathRoute(MOVE_CONTROL *psMove, int id, int startX, int sta
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}
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// Check if waiting for a result
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if (psMove->Status == MOVEWAITROUTE)
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while (psMove->Status == MOVEWAITROUTE)
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{
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PATHRESULT *psPrev = NULL, *psNext;
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objTrace(id, "Checking if we have a path yet");
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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// psNext should be _declared_ here, after the mutex lock! Used to be a race condition, thanks to -Wdeclaration-after-statement style pseudocompiler compatibility.
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psNext = firstResult;
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@ -461,7 +498,7 @@ static FPATH_RETVAL fpathRoute(MOVE_CONTROL *psMove, int id, int startX, int sta
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ASSERT(retval != FPR_OK || psMove->asPath, "Ok result but no path after copy");
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ASSERT(retval != FPR_OK || psMove->numPoints > 0, "Ok result but path empty after copy");
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free(psNext);
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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objTrace(id, "Got a path to (%d, %d)! Length=%d Retval=%d", (int)psMove->DestinationX,
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(int)psMove->DestinationY, (int)psMove->numPoints, (int)retval);
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return retval;
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@ -469,9 +506,33 @@ static FPATH_RETVAL fpathRoute(MOVE_CONTROL *psMove, int id, int startX, int sta
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psPrev = psNext;
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psNext = psNext->next;
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}
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SDL_SemPost(fpathSemaphore);
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// Sanity check that the job we are waiting for exists, at least.
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for (psJob = firstJob; psJob != NULL; psJob = psJob->next)
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{
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if (psJob->droidID == id)
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{
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goto ok;
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}
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}
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for (psNext = firstResult; psNext != NULL; psNext = psNext->next)
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{
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if (psNext->droidID == id)
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{
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goto ok;
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}
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}
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// This should never happen, but apparently does. Is psMove->Status == MOVEWAITROUTE getting synched, or something ridiculous like that?
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debug(LOG_ERROR, "Waiting for fpath result of droid %u, but the job doesn't exist. This may cause synch errors.", id);
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wzMutexUnlock(fpathMutex);
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return FPR_FAILED;
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ok:
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objTrace(id, "No path yet. Waiting.");
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return FPR_WAIT; // keep waiting
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waitingForResult = true;
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waitingForResultId = id;
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wzMutexUnlock(fpathMutex);
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wzSemaphoreWait(waitingForResultSemaphore); // keep waiting
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}
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// We were not waiting for a result, and found no trivial path, so create new job and start waiting
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@ -496,29 +557,30 @@ static FPATH_RETVAL fpathRoute(MOVE_CONTROL *psMove, int id, int startX, int sta
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// job or result for each droid in the system at any time.
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fpathRemoveDroidData(id);
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SDL_SemWait(fpathSemaphore);
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wzMutexLock(fpathMutex);
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// Add to end of list
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count = 0;
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if (!firstJob)
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{
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firstJob = psJob;
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count = 0;
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wzSemaphorePost(fpathSemaphore); // Wake up processing thread.
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}
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else
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{
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PATHJOB *psNext = firstJob;
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++count;
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count = 0;
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while (psNext->next != NULL)
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{
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psNext = psNext->next;
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count++;
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++count;
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}
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psNext->next = psJob;
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}
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SDL_SemPost(fpathSemaphore);
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wzMutexUnlock(fpathMutex);
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objTrace(id, "Queued up a path-finding request to (%d, %d), %d items earlier in queue", tX, tY, count);
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return FPR_WAIT; // wait while polling result queue
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@ -688,6 +750,7 @@ void fpathTest(int x, int y, int x2, int y2)
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/* Check initial state */
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assert(fpathThread != NULL);
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assert(fpathMutex != NULL);
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assert(fpathSemaphore != NULL);
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assert(firstJob == NULL);
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assert(firstResult == NULL);
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@ -709,7 +772,7 @@ void fpathTest(int x, int y, int x2, int y2)
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assert(fpathJobQueueLength() == 1 || fpathResultQueueLength() == 1);
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fpathRemoveDroidData(2); // should not crash, nor remove our path
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assert(fpathJobQueueLength() == 1 || fpathResultQueueLength() == 1);
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while (fpathResultQueueLength() == 0) SDL_Delay(10);
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while (fpathResultQueueLength() == 0) wzYieldCurrentThread();
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assert(fpathJobQueueLength() == 0);
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assert(fpathResultQueueLength() == 1);
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r = fpathSimpleRoute(&sMove, 1, x, y, x2, y2);
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@ -726,7 +789,7 @@ void fpathTest(int x, int y, int x2, int y2)
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r = fpathSimpleRoute(&sMove, i, x, y, x2, y2);
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assert(r == FPR_WAIT);
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}
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while (fpathResultQueueLength() != 100) SDL_Delay(10);
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while (fpathResultQueueLength() != 100) wzYieldCurrentThread();
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assert(fpathJobQueueLength() == 0);
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for (i = 1; i <= 100; i++)
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{
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