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Bug #44166 ยป lazycaps.c

Pablo Llopis, 02/17/2020 09:38 AM

 
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>

#define CEPH_IOCTL_MAGIC 0x97
#define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)

#define BUFSIZE 2097152

int main(int argc, char *argv[])
{
char buf[BUFSIZE];
int reps = 5120; //10G file
int fd;
int rank;
int numranks = 2;

if (argc != 3) {
printf("%s <filename> <rank>\n");
}

rank = atoi(argv[2]);

fd = open(argv[1], O_RDWR | O_CREAT, 0664);
if (fd >= 0)
ioctl(fd, CEPH_IOC_LAZYIO);

long unsigned int i;
for(i=0; i<reps/numranks; i++) {
memset(buf, i, BUFSIZE);
lseek(fd, i*numranks*BUFSIZE + rank*BUFSIZE, SEEK_SET);
write(fd, buf, BUFSIZE);
}
fsync(fd);
close(fd);

return 0;
}
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