Commit 5c68199029e7a3f63d43e6cb0984396460113f71
1 parent
41e17e5f11
Exists in
master
Small changes to file contention
Showing 2 changed files with 28 additions and 15 deletions Side-by-side Diff
filesystem/file_contention.c
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5c68199
| ... | ... | @@ -4,44 +4,57 @@ |
| 4 | 4 | #include <string.h> |
| 5 | 5 | #include <stdlib.h> |
| 6 | 6 | #include <sys/time.h> |
| 7 | -#define BLOCK_SIZE 1024 | |
| 7 | +#define BLOCK_SIZE 4096 | |
| 8 | + | |
| 8 | 9 | void main() |
| 9 | 10 | { |
| 10 | - char fname[10]="file_"; | |
| 11 | 11 | char buffer[BLOCK_SIZE] __attribute__ ((__aligned__ (512))); |
| 12 | 12 | struct timeval start, end; |
| 13 | 13 | int fd=0; |
| 14 | - char *file; | |
| 15 | 14 | int i = 0; |
| 16 | 15 | unsigned long long time; |
| 17 | - int status; | |
| 18 | - char *names[] = {"1", "2", "3", "4", "5", "6", "7"}; | |
| 19 | - while (i < 7) { | |
| 16 | + int child_status; | |
| 17 | + char *fnames[] = {"file_1", "file_2", "file_3", "file_4", "file_5", "file_6", | |
| 18 | + "file_7", "file_8", "file_9"}; | |
| 19 | + int numProcesses = 0; | |
| 20 | + | |
| 21 | +label: | |
| 22 | + numProcesses++; | |
| 23 | + i = 0; | |
| 24 | + printf("numProcesses: %d\n", numProcesses); | |
| 25 | + while (i < numProcesses) { | |
| 20 | 26 | int pid = fork(); |
| 21 | 27 | if (pid == 0) { |
| 22 | - file = strcat(fname, names[i]); | |
| 23 | - fd = open(fname, O_RDONLY | O_DIRECT); | |
| 28 | + //printf("Opening %d %s\n", i, fnames[i]); | |
| 29 | + fd = open(fnames[i], O_RDONLY|O_DIRECT); | |
| 30 | + fflush(stdout); | |
| 24 | 31 | if (!fd) { |
| 25 | 32 | printf("unable to open\n"); |
| 26 | - exit(0); | |
| 33 | + exit(1); | |
| 27 | 34 | } |
| 28 | - printf("accessing %n", file); | |
| 29 | - sleep(2); | |
| 30 | 35 | gettimeofday(&start, NULL); |
| 31 | - while(read(fd, buffer, BLOCK_SIZE)); | |
| 36 | + while(1) { | |
| 37 | + int rc = read(fd, buffer, BLOCK_SIZE); | |
| 38 | + if (rc < 0) { | |
| 39 | + perror("Read Error"); | |
| 40 | + exit(1); | |
| 41 | + } else if(rc == 0) | |
| 42 | + break; | |
| 43 | + } | |
| 32 | 44 | gettimeofday(&end, NULL); |
| 33 | 45 | lseek(fd, 0, SEEK_SET); |
| 34 | 46 | time = (end.tv_sec*1e6+end.tv_usec) - (start.tv_sec*1e6+start.tv_usec); |
| 35 | - // printf("timestamp %llu - %llu\n", end.tv_sec*1e6+end.tv_usec, start.tv_sec*1e6+start.tv_usec); | |
| 36 | 47 | printf("time taken to read file # %d - %llu\n", i, time); |
| 37 | 48 | sync(); |
| 38 | - status = system("sudo /sbin/sysctl vm.drop_caches=3"); | |
| 49 | + child_status = system("sudo /sbin/sysctl vm.drop_caches=3"); | |
| 39 | 50 | sync(); |
| 40 | 51 | exit(0); |
| 41 | 52 | } |
| 42 | 53 | i++; |
| 43 | 54 | } |
| 44 | 55 | sleep(10); |
| 45 | - wait(&status); | |
| 56 | + wait(&child_status); | |
| 57 | + if (numProcesses < 9) | |
| 58 | + goto label; | |
| 46 | 59 | } |
filesystem/file_contention.o
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5c68199