Attachment 920897 Details for Bug 850426 – Program to test the readahead system call

Program to test the readahead system call

ra_test.c (text/x-csrc), 1.75 KB, created by Abhijith Das on 2014-07-25 08:07:02 UTC

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Filename:

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Creator: Abhijith Das

Created: 2014-07-25 08:07:02 UTC

Size: 1.75 KB

patch

obsolete

>#define _GNU_SOURCE
>#define _ATFILE_SOURCE
>
>#include <fcntl.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <sys/syscall.h>
>#include <sys/types.h>
>#include <errno.h>
>#include <string.h>
>
>#define __NR_dir_readahead     317
>
>static __attribute__((unused))
>int dir_readahead(unsigned int fd, long long *offset, unsigned int count)
>{
>	return syscall(__NR_dir_readahead, fd, offset, count);
>}
>
>long long offset = 0;
>unsigned int count = 100000;
>const char *dirname;
>
>void print_usage(const char *prog)
>{
>	fprintf(stderr, " Usage: %s [OPTION] <dir>\n\n", prog);
>	fprintf(stderr, " -o OFFSET Offset to start dir scan from (default 0)\n");
>	fprintf(stderr, " -c COUNT  Number of entries to readahead (default 1000000)\n");
>}
>
>
>void parse_opts(int argc, char **argv)
>{
>	int opt;
>	while ((opt = getopt(argc, argv, "o:c:q")) != -1) {
>		switch (opt) {
>		case 'o':
>			offset = strtoull(optarg, NULL, 0);
>			break;
>		case 'c':
>			count = atoi(optarg);
>			break;
>		default:
>			fprintf(stderr, "Invalid argument\n");
>			print_usage(argv[0]);
>			exit(EXIT_FAILURE);
>		}
>	}
>	if (optind >= argc) {
>		fprintf(stderr, "Expected <dir> argument\n");
>		print_usage(argv[0]);
>		exit(EXIT_FAILURE);
>	}
>
>	dirname = argv[optind];
>}
>
>int main(int argc, char **argv)
>{
>	int fd, err = 0;
>
>	parse_opts(argc, argv);
>
>	fd = open(dirname, O_RDONLY | O_DIRECTORY);
>	if (fd < 0) {
>		fprintf(stderr, "open %s failed: %s\n", dirname, strerror(errno));
>		err = -1;
>		goto out;
>	}
>
>	do {
>		err = dir_readahead(fd, &offset, count);
>		if (err < 0) {
>			if (errno == EBUSY) {
>				fprintf(stderr, "busy. sleeping 1s\n");
>				sleep(1);
>				continue;
>			}
>			break;
>		}
>	} while (err);
>
>	if (err < 0)
>		fprintf(stderr, "rddir_readahead failed: %d-%s\n", errno, strerror(errno));
>	close(fd);
>
>out:
>	return err;
>}

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Attachments on bug 850426: 605960 | 617073 | 625592 | 678841 | 680222 | 680282 | 708389 | 731269 | 731270 | 731272 | 731273 | 731274 | 731278 | 731279 | 732739 | 732740 | 732845 | 834840 | 853502 | 909528 | 909529 | 909534 | 912745 | 917238 | 917239 | 920895 | 920896 | 920897 | 920898 | 920899 | 920902 | 920903 | 947987