The Tor Browser: nsprpub/pr/tests/bug1test.c@925c144e1f1f (annotated)

nsprpub/pr/tests/bug1test.c@925c144e1f1f (annotated)

nsprpub/pr/tests/bug1test.c

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

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

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nsprpub/pr/tests/bug1test.c@925c144e1f1f (annotated)

nsprpub/pr/tests/bug1test.c