1 /*
2 ** GNU Pth - The GNU Portable Threads
3 ** Copyright (c) 1999-2006 Ralf S. Engelschall <rse@engelschall.com>
4 **
5 ** This file is part of GNU Pth, a non-preemptive thread scheduling
6 ** library which can be found at http://www.gnu.org/software/pth/.
7 **
8 ** This library is free software; you can redistribute it and/or
9 ** modify it under the terms of the GNU Lesser General Public
10 ** License as published by the Free Software Foundation; either
11 ** version 2.1 of the License, or (at your option) any later version.
12 **
13 ** This library is distributed in the hope that it will be useful,
14 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
15 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 ** Lesser General Public License for more details.
17 **
18 ** You should have received a copy of the GNU Lesser General Public
19 ** License along with this library; if not, write to the Free Software
20 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
21 ** USA, or contact Ralf S. Engelschall <rse@engelschall.com>.
22 **
23 ** test_uctx.c: Pth test program (user-space context switching)
24 */
25 /* ``Engineering does not require science.
26 Science helps a lot, but people built
27 perfectly good brick walls long before
28 they knew why cement works.''
29 -- Alan Cox */
30 #include <stdio.h>
31 #include <time.h>
32
33 #include "pth.h"
34
35 volatile pth_uctx_t uctx[10];
36
37 /*
38 * Test 1: master and worker "threads"
39 */
40
41 volatile int worker_done[10];
42
worker(void * ctx)43 static void worker(void *ctx)
44 {
45 volatile int n = (int)ctx;
46 volatile int i = 0;
47
48 fprintf(stderr, "worker #%d: enter\n", n);
49 for (i = 0; i < 100; i++) {
50 fprintf(stderr, "worker #%d: working (step %d)\n", n, i);
51 pth_uctx_switch(uctx[n], uctx[0]);
52 }
53 worker_done[n] = TRUE;
54 fprintf(stderr, "worker #%d: exit\n", n);
55 return;
56 }
57
test_working(void)58 static void test_working(void)
59 {
60 volatile int i;
61 volatile int todo;
62
63 fprintf(stderr, "master: startup\n");
64
65 fprintf(stderr, "master: create contexts\n");
66 pth_uctx_create((pth_uctx_t *)&uctx[0]);
67 worker_done[0] = FALSE;
68 for (i = 1; i < 10; i++) {
69 worker_done[i] = FALSE;
70 pth_uctx_create((pth_uctx_t *)&uctx[i]);
71 pth_uctx_make(uctx[i], NULL, 32*1024, NULL, worker, (void *)i, uctx[0]);
72 }
73
74 do {
75 todo = 0;
76 for (i = 1; i < 10; i++) {
77 if (!worker_done[i]) {
78 fprintf(stderr, "master: switching to worker #%d\n", i);
79 pth_uctx_switch(uctx[0], uctx[i]);
80 fprintf(stderr, "master: came back from worker #%d\n", i);
81 todo = 1;
82 }
83 }
84 } while (todo);
85
86 fprintf(stderr, "master: destroy contexts\n");
87 for (i = 1; i < 10; i++)
88 pth_uctx_destroy(uctx[i]);
89 pth_uctx_destroy(uctx[0]);
90
91 fprintf(stderr, "master: exit\n");
92 return;
93 }
94
95 /*
96 * Test 2: raw switching performance
97 */
98
99 #define DO_SWITCHES 10000000
100
101 time_t stat_start;
102 time_t stat_end;
103 volatile int stat_switched;
104
dummy(void * ctx)105 static void dummy(void *ctx)
106 {
107 while (1) {
108 stat_switched++;
109 pth_uctx_switch(uctx[1], uctx[0]);
110 }
111 return;
112 }
113
test_performance(void)114 static void test_performance(void)
115 {
116 volatile int i;
117
118 pth_uctx_create((pth_uctx_t *)&uctx[0]);
119 pth_uctx_create((pth_uctx_t *)&uctx[1]);
120 pth_uctx_make(uctx[1], NULL, 32*1024, NULL, dummy, NULL, uctx[0]);
121
122 fprintf(stderr, "\n");
123 fprintf(stderr, "Performing %d user-space context switches... "
124 "be patient!\n", DO_SWITCHES);
125
126 stat_start = time(NULL);
127 stat_switched = 0;
128 for (i = 0; i < DO_SWITCHES; i++) {
129 stat_switched++;
130 pth_uctx_switch(uctx[0], uctx[1]);
131 }
132 stat_end = time(NULL);
133
134 pth_uctx_destroy(uctx[0]);
135 pth_uctx_destroy(uctx[1]);
136
137 fprintf(stderr, "We required %d seconds for performing the test, "
138 "so this means we can\n", (int)(stat_end-stat_start));
139 fprintf(stderr, "perform %d user-space context switches per second "
140 "on this platform.\n", DO_SWITCHES/(int)(stat_end-stat_start));
141 fprintf(stderr, "\n");
142 return;
143 }
144
main(int argc,char * argv[])145 int main(int argc, char *argv[])
146 {
147 test_working();
148 test_performance();
149 return 0;
150 }
151
152