Commit c71458d20f17ef747cb314f2526701454e35335a
1 parent
4d907d60f9
Exists in
master
Context switch working
Showing 1 changed file with 28 additions and 40 deletions Inline Diff
osproject_cswitch.c
View file @
c71458d
| /* | 1 | 1 | /* | |
| * cswitch.c -- | 2 | 2 | * cswitch.c -- | |
| * | 3 | 3 | * | |
| * Simple program to test context switching by sending short | 4 | 4 | * Simple program to test context switching by sending short | |
| * messages back and forth through a pipe. Invocation: | 5 | 5 | * messages back and forth through a pipe. Invocation: | |
| * | 6 | 6 | * | |
| * cswitch count | 7 | 7 | * cswitch count | |
| * | 8 | 8 | * | |
| * Count tells how many times a one-byte message should be sent | 9 | 9 | * Count tells how many times a one-byte message should be sent | |
| * back and forth between two processes. | 10 | 10 | * back and forth between two processes. | |
| * | 11 | 11 | * | |
| * Copyright 1987, 1989 Regents of the University of California | 12 | 12 | * Copyright 1987, 1989 Regents of the University of California | |
| * Permission to use, copy, modify, and distribute this | 13 | 13 | * Permission to use, copy, modify, and distribute this | |
| * software and its documentation for any purpose and without | 14 | 14 | * software and its documentation for any purpose and without | |
| * fee is hereby granted, provided that the above copyright | 15 | 15 | * fee is hereby granted, provided that the above copyright | |
| * notice appear in all copies. The University of California | 16 | 16 | * notice appear in all copies. The University of California | |
| * makes no representations about the suitability of this | 17 | 17 | * makes no representations about the suitability of this | |
| * software for any purpose. It is provided "as is" without | 18 | 18 | * software for any purpose. It is provided "as is" without | |
| * express or implied warranty. | 19 | 19 | * express or implied warranty. | |
| */ | 20 | 20 | */ | |
| 21 | 21 | |||
| #ifndef lint | 22 | |||
| static char rcsid[] = "$Header: /sprite/src/benchmarks/cswitch/RCS/cswitch.c,v 1.1 89/08/31 13:19:37 ouster Exp $ SPRITE (Berkeley)"; | 23 | |||
| #endif not lint | 24 | |||
| 25 | ||||
| #include <stdio.h> | 26 | 22 | #include <stdio.h> | |
| #include <sys/time.h> | 27 | 23 | int main(int argc, char **argv) | |
| 28 | ||||
| main(argc,argv) | 29 | |||
| int argc; | 30 | |||
| char **argv; | 31 | |||
| { | 32 | 24 | { | |
| int count, i, toSlave[2], fromSlave[2]; | 33 | 25 | int count, i, toSlave[2], fromSlave[2]; | |
| int pid; | 34 | 26 | int pid; | |
| char buffer[10]; | 35 | 27 | char buffer[10]; | |
| struct timeval begin ,end; | 36 | 28 | unsigned int begin ,end; | |
| int micros; | 37 | |||
| double timePer; | 38 | 29 | double timePer; | |
| extern int errno; | 39 | 30 | unsigned int regr; | |
| 31 | asm volatile("mrc p15, 0, %0, c9, c14, 0" : "=r" (regr)); | |||
| 32 | printf("regr: %x\n", regr); | |||
| 40 | 33 | |||
| if (argc != 2 ) { | 41 | 34 | count = 10; | |
| fprintf(stderr, "Ping takes one argument: count.\n"); | 42 | |||
| return; | 43 | |||
| } | 44 | |||
| count = 0; | 45 | |||
| sscanf(argv[1], "%d", &count); | 46 | |||
| pipe(toSlave); | 47 | 35 | pipe(toSlave); | |
| pipe(fromSlave); | 48 | 36 | pipe(fromSlave); | |
| pid = fork(); | 49 | 37 | pid = fork(); | |
| if (pid == 0) { | 50 | 38 | if (pid == 0) { | |
| write(fromSlave[1], "a", 1); | 51 | 39 | write(fromSlave[1], "a", 1); | |
| while (1) { | 52 | 40 | while (1) { | |
| read(toSlave[0], buffer, 1); | 53 | 41 | read(toSlave[0], buffer, 1); | |
| if (buffer[0] != 'a') { | 54 | 42 | asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (end)); | |
| exit(0); | 55 | 43 | if (buffer[0] != 'a') { | |
| } | 56 | 44 | printf("Exiting\n"); | |
| write(fromSlave[1], "a", 1); | 57 | 45 | return -1; | |
| } | 58 | 46 | } | |
| 47 | //write(fromSlave[1], "a", 1); | |||
| 48 | printf("end: %u\n", end); | |||
| 49 | } | |||
| } | 59 | 50 | } | |
| if (pid == -1) { | 60 | 51 | if (pid == -1) { | |
| fprintf(stderr, "Couldn't fork slave process: error %d.\n", | 61 | 52 | printf("Couldn't fork slave process: error %d.\n"); | |
| errno); | 62 | 53 | return; | |
| return; | 63 | 54 | } | |
| } | 64 | |||
| read(fromSlave[0], buffer, 1); | 65 | 55 | read(fromSlave[0], buffer, 1); | |
| gettimeofday(&begin, (struct timezone *) NULL); | 66 | |||
| for (i = 0; i < count; i++) { | 67 | 56 | for (i = 0; i < count; i++) { | |
| write(toSlave[1], "a", 1); | 68 | 57 | asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (begin)); | |
| read(fromSlave[0], buffer, 1); | 69 | 58 | write(toSlave[1], "a", 1); | |
| 59 | //read(fromSlave[0], buffer, 1); | |||
| 60 | usleep(10000); | |||
| 61 | printf("Start: %u\n", begin); | |||
| } | 70 | 62 | } | |
| gettimeofday(&end, (struct timezone *) NULL); | 71 | |||
| micros = 1000000*(end.tv_sec - begin.tv_sec) | 72 | |||
| + end.tv_usec - begin.tv_usec; | 73 | |||
| write(toSlave[1], "b", 1); | 74 | 63 | write(toSlave[1], "b", 1); | |
| timePer = micros; | 75 | |||
| timePer /= count * 1000; | 76 | |||
| 77 | 64 | |||
| 65 | timePer = (end - begin)/count; | |||
| printf("Elapsed time per ping (2 context switches): %.2f milliseconds.\n", | 78 | 66 | printf("Elapsed time per ping (2 context switches): %.2f milliseconds.\n", | |
| timePer); | 79 | 67 | timePer); | |
| } | 80 | 68 | } | |
| 81 | 69 | |||