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Diffstat (limited to 'nsprpub/pr/tests/bug1test.c')
| -rw-r--r-- | nsprpub/pr/tests/bug1test.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/nsprpub/pr/tests/bug1test.c b/nsprpub/pr/tests/bug1test.c new file mode 100644 index 000000000..a8df97f70 --- /dev/null +++ b/nsprpub/pr/tests/bug1test.c @@ -0,0 +1,225 @@ +/* -*- 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 */ |