michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0: Attached is a test program that uses the nspr1 to demonstrate a bug
michael@0: under NT4.0. The fix has already been mentioned (add a ResetEvent just
michael@0: before leaving the critical section in _PR_CondWait in hwmon.c).
michael@0: */
michael@0: 
michael@0: #include "prthread.h"
michael@0: #include "prtypes.h"
michael@0: #include "prinit.h"
michael@0: #include "prmon.h"
michael@0: #include "prlog.h"
michael@0: 
michael@0: typedef struct Arg_s
michael@0: {
michael@0: 	PRInt32 a, b;
michael@0: } Arg_t;
michael@0: 
michael@0: PRMonitor*  gMonitor;       // the monitor
michael@0: PRInt32     gReading;       // number of read locks
michael@0: PRInt32     gWriteWaiting;  // number of threads waiting for write lock
michael@0: PRInt32     gReadWaiting;   // number of threads waiting for read lock
michael@0: 
michael@0: PRInt32     gCounter;       // a counter
michael@0: 
michael@0:                             // stats
michael@0: PRInt32     gReads;         // number of successful reads
michael@0: PRInt32     gMaxReads;      // max number of simultaneous reads
michael@0: PRInt32     gMaxWriteWaits; // max number of writes that waited for read
michael@0: PRInt32     gMaxReadWaits;  // max number of reads that waited for write wait
michael@0: 
michael@0: 
michael@0: void spin (PRInt32 aDelay)
michael@0: {
michael@0:   PRInt32 index;
michael@0:   PRInt32 delay = aDelay * 1000;
michael@0: 
michael@0:   PR_Sleep(0);
michael@0: 
michael@0:   // randomize delay a bit
michael@0:   delay = (delay / 2) + (PRInt32)((float)delay *
michael@0: 	  ((float)rand () / (float)RAND_MAX));
michael@0: 
michael@0:   for (index = 0; index < delay * 10; index++)
michael@0: 	  // consume a bunch of cpu cycles
michael@0:     ;
michael@0:   PR_Sleep(0); 
michael@0: }
michael@0: 
michael@0: void  doWriteThread (void* arg)
michael@0: {
michael@0:   PRInt32 last;
michael@0:   Arg_t *args = (Arg_t*)arg;
michael@0:   PRInt32 aWorkDelay = args->a, aWaitDelay = args->b;
michael@0:   PR_Sleep(0);
michael@0: 
michael@0:   while (1)
michael@0:   {
michael@0:     // -- enter write lock
michael@0:     PR_EnterMonitor (gMonitor);
michael@0: 
michael@0:     if (0 < gReading)     // wait for read locks to go away
michael@0:     {
michael@0:       PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
michael@0: 
michael@0:       gWriteWaiting++;
michael@0:       if (gWriteWaiting > gMaxWriteWaits) // stats
michael@0:         gMaxWriteWaits = gWriteWaiting;
michael@0:       while (0 < gReading)
michael@0:         PR_Wait (gMonitor, fiveSecs);
michael@0:       gWriteWaiting--;
michael@0:     }
michael@0:     // -- write lock entered
michael@0: 
michael@0:     last = gCounter;
michael@0:     gCounter++;
michael@0: 
michael@0:     spin (aWorkDelay);
michael@0: 
michael@0:     PR_ASSERT (gCounter == (last + 1)); // test invariance
michael@0: 
michael@0:     // -- exit write lock        
michael@0: //    if (0 < gReadWaiting)   // notify waiting reads (do it anyway to show off the CondWait bug)
michael@0:       PR_NotifyAll (gMonitor);
michael@0: 
michael@0:     PR_ExitMonitor (gMonitor);
michael@0:     // -- write lock exited
michael@0: 
michael@0:     spin (aWaitDelay);
michael@0:   }
michael@0: }
michael@0: 
michael@0: void  doReadThread (void* arg)
michael@0: {
michael@0:   PRInt32 last;
michael@0:   Arg_t *args = (Arg_t*)arg;
michael@0:   PRInt32 aWorkDelay = args->a, aWaitDelay = args->b;
michael@0:   PR_Sleep(0);
michael@0: 
michael@0:   while (1)
michael@0:   {
michael@0:     // -- enter read lock
michael@0:     PR_EnterMonitor (gMonitor); 
michael@0: 
michael@0:     if (0 < gWriteWaiting)  // give up the monitor to waiting writes
michael@0:     {
michael@0:       PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
michael@0: 
michael@0:       gReadWaiting++;
michael@0:       if (gReadWaiting > gMaxReadWaits) // stats
michael@0:         gMaxReadWaits = gReadWaiting;
michael@0:       while (0 < gWriteWaiting)
michael@0:         PR_Wait (gMonitor, fiveSecs);
michael@0:       gReadWaiting--;
michael@0:     }
michael@0: 
michael@0:     gReading++;
michael@0: 
michael@0:     gReads++;   // stats
michael@0:     if (gReading > gMaxReads) // stats
michael@0:       gMaxReads = gReading;
michael@0: 
michael@0:     PR_ExitMonitor (gMonitor);
michael@0:     // -- read lock entered
michael@0: 
michael@0:     last = gCounter;
michael@0: 
michael@0:     spin (aWorkDelay);
michael@0: 
michael@0:     PR_ASSERT (gCounter == last); // test invariance
michael@0: 
michael@0:     // -- exit read lock
michael@0:     PR_EnterMonitor (gMonitor);  // read unlock
michael@0:     gReading--;
michael@0: 
michael@0: //    if ((0 == gReading) && (0 < gWriteWaiting))  // notify waiting writes  (do it anyway to show off the CondWait bug)
michael@0:       PR_NotifyAll (gMonitor);
michael@0:     PR_ExitMonitor (gMonitor);
michael@0:     // -- read lock exited
michael@0: 
michael@0:     spin (aWaitDelay);
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: void fireThread (
michael@0:     char* aName, void (*aProc)(void *arg), Arg_t *aArg)
michael@0: {
michael@0:   PRThread *thread = PR_CreateThread(
michael@0: 	  PR_USER_THREAD, aProc, aArg, PR_PRIORITY_NORMAL,
michael@0: 	  PR_LOCAL_THREAD, PR_UNJOINABLE_THREAD, 0);
michael@0: }
michael@0: 
michael@0: int pseudoMain (int argc, char** argv, char *pad)
michael@0: {
michael@0:   PRInt32 lastWriteCount  = gCounter;
michael@0:   PRInt32 lastReadCount   = gReads;
michael@0:   Arg_t a1 = {500, 250};
michael@0:   Arg_t a2 = {500, 500};
michael@0:   Arg_t a3 = {250, 500};
michael@0:   Arg_t a4 = {750, 250};
michael@0:   Arg_t a5 = {100, 750};
michael@0:   Arg_t a6 = {100, 500};
michael@0:   Arg_t a7 = {100, 750};
michael@0: 
michael@0:   gMonitor = PR_NewMonitor ();
michael@0: 
michael@0:   fireThread ("R1", doReadThread,   &a1);
michael@0:   fireThread ("R2", doReadThread,   &a2);
michael@0:   fireThread ("R3", doReadThread,   &a3);
michael@0:   fireThread ("R4", doReadThread,   &a4);
michael@0: 
michael@0:   fireThread ("W1", doWriteThread,  &a5);
michael@0:   fireThread ("W2", doWriteThread,  &a6);
michael@0:   fireThread ("W3", doWriteThread,  &a7);
michael@0: 
michael@0:   fireThread ("R5", doReadThread,   &a1);
michael@0:   fireThread ("R6", doReadThread,   &a2);
michael@0:   fireThread ("R7", doReadThread,   &a3);
michael@0:   fireThread ("R8", doReadThread,   &a4);
michael@0: 
michael@0:   fireThread ("W4", doWriteThread,  &a5);
michael@0:   fireThread ("W5", doWriteThread,  &a6);
michael@0:   fireThread ("W6", doWriteThread,  &a7);
michael@0:   
michael@0:   while (1)
michael@0:   {
michael@0: 	PRInt32 writeCount, readCount;
michael@0:     PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
michael@0:     PR_Sleep (fiveSecs);  // get out of the way
michael@0: 
michael@0:     // print some stats, not threadsafe, informative only
michael@0:     writeCount = gCounter;
michael@0:     readCount   = gReads;
michael@0:     printf ("\ntick %d writes (+%d), %d reads (+%d) [max %d, %d, %d]", 
michael@0:             writeCount, writeCount - lastWriteCount,
michael@0:             readCount, readCount - lastReadCount, 
michael@0:             gMaxReads, gMaxWriteWaits, gMaxReadWaits);
michael@0:     lastWriteCount = writeCount;
michael@0:     lastReadCount = readCount;
michael@0:     gMaxReads = gMaxWriteWaits = gMaxReadWaits = 0;
michael@0:   }
michael@0:   return 0;
michael@0: }
michael@0: 
michael@0: 
michael@0: static void padStack (int argc, char** argv)
michael@0: {
michael@0:   char pad[512];      /* Work around bug in nspr on windoze */
michael@0:   pseudoMain (argc, argv, pad);
michael@0: }
michael@0: 
michael@0: int main(int argc, char **argv)
michael@0: {
michael@0:   PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 0);
michael@0:   PR_STDIO_INIT();
michael@0:   padStack (argc, argv);
michael@0: }
michael@0: 
michael@0: 
michael@0: /* bug1test.c */