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 /* -*- 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/. */

 /*

 ** File:            switch.c

 ** Description:     trying to time context switches

 */

 #include "prinit.h"

 #include "prcvar.h"

 #include "prmem.h"

 #include "prinrval.h"

 #include "prlock.h"

 #include "prlog.h"

 #include "prthread.h"

 #include "prprf.h"

 #include "plerror.h"

 #include "plgetopt.h"

 #include "private/pprio.h"

 #include <stdlib.h>

 #define INNER_LOOPS 100

 #define DEFAULT_LOOPS 100

 #define DEFAULT_THREADS 10

 static PRFileDesc *debug_out = NULL;

 static PRBool debug_mode = PR_FALSE, verbosity = PR_FALSE, failed = PR_FALSE;

 typedef struct Shared

 {

     PRLock *ml;

     PRCondVar *cv;

     PRBool twiddle;

     PRThread *thread;

     struct Shared *next;

 } Shared;

 static void Help(void)

 {

     debug_out = PR_STDOUT;

     PR_fprintf(

 		debug_out, "Usage: >./switch [-c n] [-t n] [-d] [-v] [-G] [-C n]\n");

     PR_fprintf(

 		debug_out, "-c n\tloops at thread level (default: %d)\n", DEFAULT_LOOPS);

     PR_fprintf(

 		debug_out, "-t n\tnumber of threads (default: %d)\n", DEFAULT_THREADS);

     PR_fprintf(debug_out, "-d\tturn on debugging output (default: FALSE)\n");

     PR_fprintf(debug_out, "-v\tturn on verbose output (default: FALSE)\n");

     PR_fprintf(debug_out, "-G\tglobal threads only (default: FALSE)\n");

     PR_fprintf(debug_out, "-C n\tconcurrency setting (default: 1)\n");

 }  /* Help */

 static void PR_CALLBACK Notified(void *arg)

 {

     Shared *shared = (Shared*)arg;

     PRStatus status = PR_SUCCESS;

     while (PR_SUCCESS == status)

     {

         PR_Lock(shared->ml);

         while (shared->twiddle && (PR_SUCCESS == status))

             status = PR_WaitCondVar(shared->cv, PR_INTERVAL_NO_TIMEOUT);

 		if (verbosity) PR_fprintf(debug_out, "+");

         shared->twiddle = PR_TRUE;

         shared->next->twiddle = PR_FALSE;

         PR_NotifyCondVar(shared->next->cv);

         PR_Unlock(shared->ml);

     }

 }  /* Notified */

 static Shared home;

 PRIntn PR_CALLBACK Switch(PRIntn argc, char **argv)

 {

 	PLOptStatus os;

     PRStatus status;

     PRBool help = PR_FALSE;

     PRUintn concurrency = 1;

     Shared *shared, *link;

     PRIntervalTime timein, timeout;

     PRThreadScope thread_scope = PR_LOCAL_THREAD;

     PRUintn thread_count, inner_count, loop_count, average;

     PRUintn thread_limit = DEFAULT_THREADS, loop_limit = DEFAULT_LOOPS;

 	PLOptState *opt = PL_CreateOptState(argc, argv, "hdvc:t:C:G");

 	while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))

     {

 		if (PL_OPT_BAD == os) continue;

         switch (opt->option)

         {

         case 'v':  /* verbose mode */

 			verbosity = PR_TRUE;

         case 'd':  /* debug mode */

 			debug_mode = PR_TRUE;

             break;

         case 'c':  /* loop counter */

 			loop_limit = atoi(opt->value);

             break;

         case 't':  /* thread limit */

 			thread_limit = atoi(opt->value);

             break;

         case 'C':  /* Concurrency limit */

 			concurrency = atoi(opt->value);

             break;

         case 'G':  /* global threads only */

 			thread_scope = PR_GLOBAL_THREAD;

             break;

         case 'h':  /* help message */

 			Help();

 			help = PR_TRUE;

             break;

          default:

             break;

         }

     }

 	PL_DestroyOptState(opt);

     if (help) return -1;

 	if (PR_TRUE == debug_mode)

 	{

 		debug_out = PR_STDOUT;

 		PR_fprintf(debug_out, "Test parameters\n");

 		PR_fprintf(debug_out, "\tThreads involved: %d\n", thread_limit);

 		PR_fprintf(debug_out, "\tIteration limit: %d\n", loop_limit);

 		PR_fprintf(debug_out, "\tConcurrency: %d\n", concurrency);

 		PR_fprintf(

 			debug_out, "\tThread type: %s\n",

 			(PR_GLOBAL_THREAD == thread_scope) ? "GLOBAL" : "LOCAL");

 	}

     PR_SetConcurrency(concurrency);

     link = &home;

     home.ml = PR_NewLock();

     home.cv = PR_NewCondVar(home.ml);

     home.twiddle = PR_FALSE;

     home.next = NULL;

     timeout = 0;

     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)

     {

         shared = PR_NEWZAP(Shared);

         shared->ml = home.ml;

         shared->cv = PR_NewCondVar(home.ml);

         shared->twiddle = PR_TRUE;

         shared->next = link;

         link = shared;

         shared->thread = PR_CreateThread(

             PR_USER_THREAD, Notified, shared,

             PR_PRIORITY_HIGH, thread_scope,

             PR_JOINABLE_THREAD, 0);

         PR_ASSERT(shared->thread != NULL);

         if (NULL == shared->thread)

             failed = PR_TRUE;

 	}

     for (loop_count = 1; loop_count <= loop_limit; ++loop_count)

     {

 		timein = PR_IntervalNow();

 		for (inner_count = 0; inner_count < INNER_LOOPS; ++inner_count)

 		{

 			PR_Lock(home.ml);

 			home.twiddle = PR_TRUE;

 			shared->twiddle = PR_FALSE;

 			PR_NotifyCondVar(shared->cv);

 			while (home.twiddle)

             {

 				status = PR_WaitCondVar(home.cv, PR_INTERVAL_NO_TIMEOUT);

 				if (PR_FAILURE == status)

 				    failed = PR_TRUE;

             }

 			PR_Unlock(home.ml);

 		}

 		timeout += (PR_IntervalNow() - timein);

 	}

 	if (debug_mode)

 	{

 		average = PR_IntervalToMicroseconds(timeout)

 			/ (INNER_LOOPS * loop_limit * thread_count);

 		PR_fprintf(

 			debug_out, "Average switch times %d usecs for %d threads\n",

             average, thread_limit);

 	}

     link = shared;

     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)

     {

         if (&home == link) break;

         status = PR_Interrupt(link->thread);

 		if (PR_SUCCESS != status)

         {

             failed = PR_TRUE;

             if (debug_mode)

 			    PL_FPrintError(debug_out, "Failed to interrupt");

         }

 		link = link->next; 

     }

     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)

     {

         link = shared->next;

         status = PR_JoinThread(shared->thread);

 		if (PR_SUCCESS != status)

 		{

             failed = PR_TRUE;

             if (debug_mode)

 			    PL_FPrintError(debug_out, "Failed to join");

         }

         PR_DestroyCondVar(shared->cv);

         PR_DELETE(shared);

         if (&home == link) break;

         shared = link;

     }

     PR_DestroyCondVar(home.cv);

     PR_DestroyLock(home.ml);

     PR_fprintf(PR_STDOUT, ((failed) ? "FAILED\n" : "PASSED\n"));

     return ((failed) ? 1 : 0);

 }  /* Switch */

 int main(int argc, char **argv)

 {

     PRIntn result;

     PR_STDIO_INIT();

     result = PR_Initialize(Switch, argc, argv, 0);

     return result;

 }  /* main */

 /* switch.c */