1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3  * License, v. 2.0. If a copy of the MPL was not distributed with this
4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 
6 /*
7 ** File:            switch.c
8 ** Description:     trying to time context switches
9 */
10 
11 #include "prinit.h"
12 #include "prcvar.h"
13 #include "prmem.h"
14 #include "prinrval.h"
15 #include "prlock.h"
16 #include "prlog.h"
17 #include "prthread.h"
18 #include "prprf.h"
19 
20 #include "plerror.h"
21 #include "plgetopt.h"
22 
23 #include "private/pprio.h"
24 
25 #include <stdlib.h>
26 
27 #define INNER_LOOPS 100
28 #define DEFAULT_LOOPS 100
29 #define DEFAULT_THREADS 10
30 
31 static PRFileDesc *debug_out = NULL;
32 static PRBool debug_mode = PR_FALSE, verbosity = PR_FALSE, failed = PR_FALSE;
33 
34 typedef struct Shared
35 {
36     PRLock *ml;
37     PRCondVar *cv;
38     PRBool twiddle;
39     PRThread *thread;
40     struct Shared *next;
41 } Shared;
42 
Help(void)43 static void Help(void)
44 {
45     debug_out = PR_STDOUT;
46 
47     PR_fprintf(
48 		debug_out, "Usage: >./switch [-c n] [-t n] [-d] [-v] [-G] [-C n]\n");
49     PR_fprintf(
50 		debug_out, "-c n\tloops at thread level (default: %d)\n", DEFAULT_LOOPS);
51     PR_fprintf(
52 		debug_out, "-t n\tnumber of threads (default: %d)\n", DEFAULT_THREADS);
53     PR_fprintf(debug_out, "-d\tturn on debugging output (default: FALSE)\n");
54     PR_fprintf(debug_out, "-v\tturn on verbose output (default: FALSE)\n");
55     PR_fprintf(debug_out, "-G\tglobal threads only (default: FALSE)\n");
56     PR_fprintf(debug_out, "-C n\tconcurrency setting (default: 1)\n");
57 }  /* Help */
58 
Notified(void * arg)59 static void PR_CALLBACK Notified(void *arg)
60 {
61     Shared *shared = (Shared*)arg;
62     PRStatus status = PR_SUCCESS;
63     while (PR_SUCCESS == status)
64     {
65         PR_Lock(shared->ml);
66         while (shared->twiddle && (PR_SUCCESS == status))
67             status = PR_WaitCondVar(shared->cv, PR_INTERVAL_NO_TIMEOUT);
68 		if (verbosity) PR_fprintf(debug_out, "+");
69         shared->twiddle = PR_TRUE;
70         shared->next->twiddle = PR_FALSE;
71         PR_NotifyCondVar(shared->next->cv);
72         PR_Unlock(shared->ml);
73     }
74 }  /* Notified */
75 
76 static Shared home;
Switch(PRIntn argc,char ** argv)77 PRIntn PR_CALLBACK Switch(PRIntn argc, char **argv)
78 {
79 	PLOptStatus os;
80     PRStatus status;
81     PRBool help = PR_FALSE;
82     PRUintn concurrency = 1;
83     Shared *shared, *link;
84     PRIntervalTime timein, timeout;
85     PRThreadScope thread_scope = PR_LOCAL_THREAD;
86     PRUintn thread_count, inner_count, loop_count, average;
87     PRUintn thread_limit = DEFAULT_THREADS, loop_limit = DEFAULT_LOOPS;
88 	PLOptState *opt = PL_CreateOptState(argc, argv, "hdvc:t:C:G");
89 	while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
90     {
91 		if (PL_OPT_BAD == os) continue;
92         switch (opt->option)
93         {
94         case 'v':  /* verbose mode */
95 			verbosity = PR_TRUE;
96         case 'd':  /* debug mode */
97 			debug_mode = PR_TRUE;
98             break;
99         case 'c':  /* loop counter */
100 			loop_limit = atoi(opt->value);
101             break;
102         case 't':  /* thread limit */
103 			thread_limit = atoi(opt->value);
104             break;
105         case 'C':  /* Concurrency limit */
106 			concurrency = atoi(opt->value);
107             break;
108         case 'G':  /* global threads only */
109 			thread_scope = PR_GLOBAL_THREAD;
110             break;
111         case 'h':  /* help message */
112 			Help();
113 			help = PR_TRUE;
114             break;
115          default:
116             break;
117         }
118     }
119 	PL_DestroyOptState(opt);
120 
121     if (help) return -1;
122 
123 	if (PR_TRUE == debug_mode)
124 	{
125 		debug_out = PR_STDOUT;
126 		PR_fprintf(debug_out, "Test parameters\n");
127 		PR_fprintf(debug_out, "\tThreads involved: %d\n", thread_limit);
128 		PR_fprintf(debug_out, "\tIteration limit: %d\n", loop_limit);
129 		PR_fprintf(debug_out, "\tConcurrency: %d\n", concurrency);
130 		PR_fprintf(
131 			debug_out, "\tThread type: %s\n",
132 			(PR_GLOBAL_THREAD == thread_scope) ? "GLOBAL" : "LOCAL");
133 	}
134 
135     PR_SetConcurrency(concurrency);
136 
137     link = &home;
138     home.ml = PR_NewLock();
139     home.cv = PR_NewCondVar(home.ml);
140     home.twiddle = PR_FALSE;
141     home.next = NULL;
142 
143     timeout = 0;
144 
145     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
146     {
147         shared = PR_NEWZAP(Shared);
148 
149         shared->ml = home.ml;
150         shared->cv = PR_NewCondVar(home.ml);
151         shared->twiddle = PR_TRUE;
152         shared->next = link;
153         link = shared;
154 
155         shared->thread = PR_CreateThread(
156             PR_USER_THREAD, Notified, shared,
157             PR_PRIORITY_HIGH, thread_scope,
158             PR_JOINABLE_THREAD, 0);
159         PR_ASSERT(shared->thread != NULL);
160         if (NULL == shared->thread)
161             failed = PR_TRUE;
162 	}
163 
164     for (loop_count = 1; loop_count <= loop_limit; ++loop_count)
165     {
166 		timein = PR_IntervalNow();
167 		for (inner_count = 0; inner_count < INNER_LOOPS; ++inner_count)
168 		{
169 			PR_Lock(home.ml);
170 			home.twiddle = PR_TRUE;
171 			shared->twiddle = PR_FALSE;
172 			PR_NotifyCondVar(shared->cv);
173 			while (home.twiddle)
174             {
175 				status = PR_WaitCondVar(home.cv, PR_INTERVAL_NO_TIMEOUT);
176 				if (PR_FAILURE == status)
177 				    failed = PR_TRUE;
178             }
179 			PR_Unlock(home.ml);
180 		}
181 		timeout += (PR_IntervalNow() - timein);
182 	}
183 
184 	if (debug_mode)
185 	{
186 		average = PR_IntervalToMicroseconds(timeout)
187 			/ (INNER_LOOPS * loop_limit * thread_count);
188 		PR_fprintf(
189 			debug_out, "Average switch times %d usecs for %d threads\n",
190             average, thread_limit);
191 	}
192 
193     link = shared;
194     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
195     {
196         if (&home == link) break;
197         status = PR_Interrupt(link->thread);
198 		if (PR_SUCCESS != status)
199         {
200             failed = PR_TRUE;
201             if (debug_mode)
202 			    PL_FPrintError(debug_out, "Failed to interrupt");
203         }
204 		link = link->next;
205     }
206 
207     for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
208     {
209         link = shared->next;
210         status = PR_JoinThread(shared->thread);
211 		if (PR_SUCCESS != status)
212 		{
213             failed = PR_TRUE;
214             if (debug_mode)
215 			    PL_FPrintError(debug_out, "Failed to join");
216         }
217         PR_DestroyCondVar(shared->cv);
218         PR_DELETE(shared);
219         if (&home == link) break;
220         shared = link;
221     }
222     PR_DestroyCondVar(home.cv);
223     PR_DestroyLock(home.ml);
224 
225     PR_fprintf(PR_STDOUT, ((failed) ? "FAILED\n" : "PASSED\n"));
226     return ((failed) ? 1 : 0);
227 }  /* Switch */
228 
main(int argc,char ** argv)229 int main(int argc, char **argv)
230 {
231     PRIntn result;
232     PR_STDIO_INIT();
233     result = PR_Initialize(Switch, argc, argv, 0);
234     return result;
235 }  /* main */
236 
237 /* switch.c */
238