1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/nsprpub/pr/tests/bug1test.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,225 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/*
1.10 +Attached is a test program that uses the nspr1 to demonstrate a bug
1.11 +under NT4.0. The fix has already been mentioned (add a ResetEvent just
1.12 +before leaving the critical section in _PR_CondWait in hwmon.c).
1.13 +*/
1.14 +
1.15 +#include "prthread.h"
1.16 +#include "prtypes.h"
1.17 +#include "prinit.h"
1.18 +#include "prmon.h"
1.19 +#include "prlog.h"
1.20 +
1.21 +typedef struct Arg_s
1.22 +{
1.23 + PRInt32 a, b;
1.24 +} Arg_t;
1.25 +
1.26 +PRMonitor* gMonitor; // the monitor
1.27 +PRInt32 gReading; // number of read locks
1.28 +PRInt32 gWriteWaiting; // number of threads waiting for write lock
1.29 +PRInt32 gReadWaiting; // number of threads waiting for read lock
1.30 +
1.31 +PRInt32 gCounter; // a counter
1.32 +
1.33 + // stats
1.34 +PRInt32 gReads; // number of successful reads
1.35 +PRInt32 gMaxReads; // max number of simultaneous reads
1.36 +PRInt32 gMaxWriteWaits; // max number of writes that waited for read
1.37 +PRInt32 gMaxReadWaits; // max number of reads that waited for write wait
1.38 +
1.39 +
1.40 +void spin (PRInt32 aDelay)
1.41 +{
1.42 + PRInt32 index;
1.43 + PRInt32 delay = aDelay * 1000;
1.44 +
1.45 + PR_Sleep(0);
1.46 +
1.47 + // randomize delay a bit
1.48 + delay = (delay / 2) + (PRInt32)((float)delay *
1.49 + ((float)rand () / (float)RAND_MAX));
1.50 +
1.51 + for (index = 0; index < delay * 10; index++)
1.52 + // consume a bunch of cpu cycles
1.53 + ;
1.54 + PR_Sleep(0);
1.55 +}
1.56 +
1.57 +void doWriteThread (void* arg)
1.58 +{
1.59 + PRInt32 last;
1.60 + Arg_t *args = (Arg_t*)arg;
1.61 + PRInt32 aWorkDelay = args->a, aWaitDelay = args->b;
1.62 + PR_Sleep(0);
1.63 +
1.64 + while (1)
1.65 + {
1.66 + // -- enter write lock
1.67 + PR_EnterMonitor (gMonitor);
1.68 +
1.69 + if (0 < gReading) // wait for read locks to go away
1.70 + {
1.71 + PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
1.72 +
1.73 + gWriteWaiting++;
1.74 + if (gWriteWaiting > gMaxWriteWaits) // stats
1.75 + gMaxWriteWaits = gWriteWaiting;
1.76 + while (0 < gReading)
1.77 + PR_Wait (gMonitor, fiveSecs);
1.78 + gWriteWaiting--;
1.79 + }
1.80 + // -- write lock entered
1.81 +
1.82 + last = gCounter;
1.83 + gCounter++;
1.84 +
1.85 + spin (aWorkDelay);
1.86 +
1.87 + PR_ASSERT (gCounter == (last + 1)); // test invariance
1.88 +
1.89 + // -- exit write lock
1.90 +// if (0 < gReadWaiting) // notify waiting reads (do it anyway to show off the CondWait bug)
1.91 + PR_NotifyAll (gMonitor);
1.92 +
1.93 + PR_ExitMonitor (gMonitor);
1.94 + // -- write lock exited
1.95 +
1.96 + spin (aWaitDelay);
1.97 + }
1.98 +}
1.99 +
1.100 +void doReadThread (void* arg)
1.101 +{
1.102 + PRInt32 last;
1.103 + Arg_t *args = (Arg_t*)arg;
1.104 + PRInt32 aWorkDelay = args->a, aWaitDelay = args->b;
1.105 + PR_Sleep(0);
1.106 +
1.107 + while (1)
1.108 + {
1.109 + // -- enter read lock
1.110 + PR_EnterMonitor (gMonitor);
1.111 +
1.112 + if (0 < gWriteWaiting) // give up the monitor to waiting writes
1.113 + {
1.114 + PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
1.115 +
1.116 + gReadWaiting++;
1.117 + if (gReadWaiting > gMaxReadWaits) // stats
1.118 + gMaxReadWaits = gReadWaiting;
1.119 + while (0 < gWriteWaiting)
1.120 + PR_Wait (gMonitor, fiveSecs);
1.121 + gReadWaiting--;
1.122 + }
1.123 +
1.124 + gReading++;
1.125 +
1.126 + gReads++; // stats
1.127 + if (gReading > gMaxReads) // stats
1.128 + gMaxReads = gReading;
1.129 +
1.130 + PR_ExitMonitor (gMonitor);
1.131 + // -- read lock entered
1.132 +
1.133 + last = gCounter;
1.134 +
1.135 + spin (aWorkDelay);
1.136 +
1.137 + PR_ASSERT (gCounter == last); // test invariance
1.138 +
1.139 + // -- exit read lock
1.140 + PR_EnterMonitor (gMonitor); // read unlock
1.141 + gReading--;
1.142 +
1.143 +// if ((0 == gReading) && (0 < gWriteWaiting)) // notify waiting writes (do it anyway to show off the CondWait bug)
1.144 + PR_NotifyAll (gMonitor);
1.145 + PR_ExitMonitor (gMonitor);
1.146 + // -- read lock exited
1.147 +
1.148 + spin (aWaitDelay);
1.149 + }
1.150 +}
1.151 +
1.152 +
1.153 +void fireThread (
1.154 + char* aName, void (*aProc)(void *arg), Arg_t *aArg)
1.155 +{
1.156 + PRThread *thread = PR_CreateThread(
1.157 + PR_USER_THREAD, aProc, aArg, PR_PRIORITY_NORMAL,
1.158 + PR_LOCAL_THREAD, PR_UNJOINABLE_THREAD, 0);
1.159 +}
1.160 +
1.161 +int pseudoMain (int argc, char** argv, char *pad)
1.162 +{
1.163 + PRInt32 lastWriteCount = gCounter;
1.164 + PRInt32 lastReadCount = gReads;
1.165 + Arg_t a1 = {500, 250};
1.166 + Arg_t a2 = {500, 500};
1.167 + Arg_t a3 = {250, 500};
1.168 + Arg_t a4 = {750, 250};
1.169 + Arg_t a5 = {100, 750};
1.170 + Arg_t a6 = {100, 500};
1.171 + Arg_t a7 = {100, 750};
1.172 +
1.173 + gMonitor = PR_NewMonitor ();
1.174 +
1.175 + fireThread ("R1", doReadThread, &a1);
1.176 + fireThread ("R2", doReadThread, &a2);
1.177 + fireThread ("R3", doReadThread, &a3);
1.178 + fireThread ("R4", doReadThread, &a4);
1.179 +
1.180 + fireThread ("W1", doWriteThread, &a5);
1.181 + fireThread ("W2", doWriteThread, &a6);
1.182 + fireThread ("W3", doWriteThread, &a7);
1.183 +
1.184 + fireThread ("R5", doReadThread, &a1);
1.185 + fireThread ("R6", doReadThread, &a2);
1.186 + fireThread ("R7", doReadThread, &a3);
1.187 + fireThread ("R8", doReadThread, &a4);
1.188 +
1.189 + fireThread ("W4", doWriteThread, &a5);
1.190 + fireThread ("W5", doWriteThread, &a6);
1.191 + fireThread ("W6", doWriteThread, &a7);
1.192 +
1.193 + while (1)
1.194 + {
1.195 + PRInt32 writeCount, readCount;
1.196 + PRIntervalTime fiveSecs = PR_SecondsToInterval(5);
1.197 + PR_Sleep (fiveSecs); // get out of the way
1.198 +
1.199 + // print some stats, not threadsafe, informative only
1.200 + writeCount = gCounter;
1.201 + readCount = gReads;
1.202 + printf ("\ntick %d writes (+%d), %d reads (+%d) [max %d, %d, %d]",
1.203 + writeCount, writeCount - lastWriteCount,
1.204 + readCount, readCount - lastReadCount,
1.205 + gMaxReads, gMaxWriteWaits, gMaxReadWaits);
1.206 + lastWriteCount = writeCount;
1.207 + lastReadCount = readCount;
1.208 + gMaxReads = gMaxWriteWaits = gMaxReadWaits = 0;
1.209 + }
1.210 + return 0;
1.211 +}
1.212 +
1.213 +
1.214 +static void padStack (int argc, char** argv)
1.215 +{
1.216 + char pad[512]; /* Work around bug in nspr on windoze */
1.217 + pseudoMain (argc, argv, pad);
1.218 +}
1.219 +
1.220 +int main(int argc, char **argv)
1.221 +{
1.222 + PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 0);
1.223 + PR_STDIO_INIT();
1.224 + padStack (argc, argv);
1.225 +}
1.226 +
1.227 +
1.228 +/* bug1test.c */
