// Read lbns l1 and l2 back-to-back, timing the second request. In
// trace generation mode, we just print out the IOs we would do. In
// calibration mode, we inject both IOs into an instance of disksim.
double
time_second_request(int l1, int l2, struct dsstuff *ds, struct trace *t,
struct dm_disk_if *d) {
struct disksim_request *r1, *r2;
ddbg_assert(l1 < d->dm_sectors);
ddbg_assert(l2 < d->dm_sectors);
if(mode == GENTRACE) {
fprintf(t->fp, "%f 0 %d 1 1\n", ds->now, l1);
fprintf(t->fp, "%f 0 %d 1 1\n", ds->now + 0.1, l2);
ds->now += 20.0;
} else {
r1 = calloc(1, sizeof(*r1));
r2 = calloc(1, sizeof(*r2));
r1->blkno = l1;
r1->bytecount = 512;
r1->flags |= DISKSIM_READ;
r1->start = ds->now;
// r1->reqctx = &t1;
r2->blkno = l2;
r2->bytecount = 512;
r2->flags |= DISKSIM_READ;
r2->start = ds->now + 0.001;
// r2->reqctx = &t2;
disksim_interface_request_arrive(ds->iface, ds->now, r1);
disksim_interface_request_arrive(ds->iface, ds->now, r2);
// pump disksim
do {
ds->now = ds->next;
ds->next = -1;
disksim_interface_internal_event(ds->iface, ds->now, 0);
} while(ds->next != -1);
// roll now forward slightly, some small ~1ms int-arr
ds->now += 1.0;
free(r1);
free(r2);
// printf("%d -> %d : %f\n", l1, l2, ds->compl[1] - ds->compl[0]);
ds->compl_next = 0;
}
return ds->compl[1] - ds->compl[0];
}
int seek_sim(
struct disksim_interface *disksim,
const int measurements,
const size_t sector_size,
const int write_flag)
{
double t;
double sum;
unsigned long pos=0;
int nbytes;
int i;
struct disksim_request r;
int base = 0;
fprintf(stdout, "# Seek distances measured: %d\n", measurements);
sum = 0;
// for ( base = 0; base < sector_size*measurements; base += sector_size )
// for ( base = 0; base < sector_size*1000; base += 4096 )
{
pos = 0;
for (i=0; i<measurements; i++)
{
r.start = now;
// r.flags = DISKSIM_READ;
r.flags = DISKSIM_WRITE;
r.devno = 0;
r.bytecount = sector_size;
// r.blkno = base; r.blkno = base;
r.blkno = 0;
/* reset the disk position */
if (write_flag) {
r.flags = DISKSIM_WRITE;
}
disksim_interface_request_arrive(disksim, now, &r);
/* Process events until this I/O is completed */
while(next_event >= 0) {
now = next_event;
next_event = -1;
disksim_interface_internal_event(disksim, now, 0);
}
pos = 0;
/* save the current time */
/* lseek(fd, i*sector_size, SEEK_CUR) */
r.start = now;
r.flags = DISKSIM_WRITE;
r.devno = 0;
r.bytecount = sector_size;
r.blkno = i+base/sector_size;
/* reset the disk position */
if (write_flag) {
r.flags = DISKSIM_WRITE;
}
t = now;
disksim_interface_request_arrive(disksim, now, &r);
/* Process events until this I/O is completed */
while(next_event >= 0) {
now = next_event;
next_event = -1;
disksim_interface_internal_event(disksim, now, 0);
}
fprintf(stdout, "%d %lf\n", i, now-t);
}
}
return 0;
}
int
main(int argc, char *argv[])
{
int i;
int nsectors;
struct stat buf;
struct disksim_request r;
struct disksim_interface *disksim;
unsigned long pos=0;
int measurements;
struct stat;
int len = 8192000;
int test_encapsulation;
struct disksim_interface* iface;
struct gengetopt_args_info args_info;
double t;
if (argc != 4 || (measurements = atoi(argv[3])) <= 0) {
fprintf(stderr, "usage: %s <param file> <output file> <#measurements>\n",
argv[0]);
exit(1);
}
if (stat(argv[1], &buf) < 0)
panic(argv[1]);
disksim = disksim_interface_initialize(argv[1],
argv[2],
syssim_report_completion,
syssim_schedule_callback,
syssim_deschedule_callback,
0,
0,
0);
/* NOTE: it is bad to use this internal disksim call from external... */
DISKSIM_srand48(1);
for (i=0; i < measurements; i++) {
r.start = now;
r.flags = DISKSIM_READ;
r.devno = 0;
/* NOTE: it is bad to use this internal disksim call from external... */
r.blkno = pos; //BLOCK2SECTOR*(DISKSIM_lrand48()%(nsectors/BLOCK2SECTOR));
r.bytecount = SECTOR;
completed = 0;
t = now;
disksim_interface_request_arrive(disksim, now, &r);
/* Process events until this I/O is completed */
while(next_event >= 0) {
now = next_event;
next_event = -1;
disksim_interface_internal_event(disksim, now, 0);
}
pos+= SECTOR;
fprintf(stdout, "%d %g\n",i,(now-t)*1000.0);
if (!completed) {
fprintf(stderr,
"%s: internal error. Last event not completed %d\n",
argv[0], i);
exit(1);
}
}
disksim_interface_shutdown(disksim, now);
print_statistics(&st, "response time");
exit(0);
}
