pre_read fixes
[fio.git] / engines / cpu.c
CommitLineData
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1/*
2 * CPU engine
3 *
4 * Doesn't transfer any data, merely burns CPU cycles according to
5 * the settings.
6 *
7 */
5f350952 8#include "../fio.h"
2866c82d 9
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10static int fio_cpuio_queue(struct thread_data *td, struct io_u fio_unused *io_u)
11{
6dd6f2cd 12 usec_spin(td->o.cpucycle);
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13 return FIO_Q_COMPLETED;
14}
15
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16static int fio_cpuio_init(struct thread_data *td)
17{
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18 struct thread_options *o = &td->o;
19
20 if (!o->cpuload) {
ba0fbe10 21 td_vmsg(td, EINVAL, "cpu thread needs rate (cpuload=)","cpuio");
2866c82d 22 return 1;
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23 }
24
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25 if (o->cpuload > 100)
26 o->cpuload = 100;
2866c82d 27
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28 /*
29 * set thinktime_sleep and thinktime_spin appropriately
30 */
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31 o->thinktime_blocks = 1;
32 o->thinktime_spin = 0;
33 o->thinktime = (o->cpucycle * (100 - o->cpuload)) / o->cpuload;
2866c82d 34
2dc1bbeb 35 o->nr_files = o->open_files = 1;
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36 return 0;
37}
38
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39static int fio_cpuio_open(struct thread_data fio_unused *td,
40 struct fio_file fio_unused *f)
ba0fbe10 41{
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42 return 0;
43}
44
5f350952 45static struct ioengine_ops ioengine = {
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46 .name = "cpuio",
47 .version = FIO_IOOPS_VERSION,
ba0fbe10 48 .queue = fio_cpuio_queue,
2866c82d 49 .init = fio_cpuio_init,
ba0fbe10 50 .open_file = fio_cpuio_open,
1f809d15 51 .flags = FIO_SYNCIO | FIO_DISKLESSIO | FIO_NOIO,
2866c82d 52};
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53
54static void fio_init fio_cpuio_register(void)
55{
56 register_ioengine(&ioengine);
57}
58
59static void fio_exit fio_cpuio_unregister(void)
60{
61 unregister_ioengine(&ioengine);
62}