1/*
2 * CPU engine
3 *
4 * Doesn't transfer any data, merely burns CPU cycles according to
5 * the settings.
6 *
7 */
8#include "../fio.h"
9
10struct cpu_options {
11	struct thread_data *td;
12	unsigned int cpuload;
13	unsigned int cpucycle;
14	unsigned int exit_io_done;
15};
16
17static struct fio_option options[] = {
18	{
19		.name	= "cpuload",
20		.lname	= "CPU load",
21		.type	= FIO_OPT_INT,
22		.off1	= offsetof(struct cpu_options, cpuload),
23		.help	= "Use this percentage of CPU",
24		.category = FIO_OPT_C_GENERAL,
25		.group	= FIO_OPT_G_INVALID,
26	},
27	{
28		.name	= "cpuchunks",
29		.lname	= "CPU chunk",
30		.type	= FIO_OPT_INT,
31		.off1	= offsetof(struct cpu_options, cpucycle),
32		.help	= "Length of the CPU burn cycles (usecs)",
33		.def	= "50000",
34		.parent = "cpuload",
35		.hide	= 1,
36		.category = FIO_OPT_C_GENERAL,
37		.group	= FIO_OPT_G_INVALID,
38	},
39	{
40		.name	= "exit_on_io_done",
41		.lname	= "Exit when IO threads are done",
42		.type	= FIO_OPT_BOOL,
43		.off1	= offsetof(struct cpu_options, exit_io_done),
44		.help	= "Exit when IO threads finish",
45		.def	= "0",
46		.category = FIO_OPT_C_GENERAL,
47		.group	= FIO_OPT_G_INVALID,
48	},
49	{
50		.name	= NULL,
51	},
52};
53
54
55static int fio_cpuio_queue(struct thread_data *td, struct io_u fio_unused *io_u)
56{
57	struct cpu_options *co = td->eo;
58
59	if (co->exit_io_done && !fio_running_or_pending_io_threads()) {
60		td->done = 1;
61		return FIO_Q_BUSY;
62	}
63
64	usec_spin(co->cpucycle);
65	return FIO_Q_COMPLETED;
66}
67
68static int fio_cpuio_init(struct thread_data *td)
69{
70	struct thread_options *o = &td->o;
71	struct cpu_options *co = td->eo;
72
73	if (!co->cpuload) {
74		td_vmsg(td, EINVAL, "cpu thread needs rate (cpuload=)","cpuio");
75		return 1;
76	}
77
78	if (co->cpuload > 100)
79		co->cpuload = 100;
80
81	/*
82	 * set thinktime_sleep and thinktime_spin appropriately
83	 */
84	o->thinktime_blocks = 1;
85	o->thinktime_spin = 0;
86	o->thinktime = (co->cpucycle * (100 - co->cpuload)) / co->cpuload;
87
88	o->nr_files = o->open_files = 1;
89
90	log_info("%s: ioengine=cpu, cpuload=%u, cpucycle=%u\n", td->o.name,
91						co->cpuload, co->cpucycle);
92
93	return 0;
94}
95
96static int fio_cpuio_open(struct thread_data fio_unused *td,
97			  struct fio_file fio_unused *f)
98{
99	return 0;
100}
101
102static struct ioengine_ops ioengine = {
103	.name		= "cpuio",
104	.version	= FIO_IOOPS_VERSION,
105	.queue		= fio_cpuio_queue,
106	.init		= fio_cpuio_init,
107	.open_file	= fio_cpuio_open,
108	.flags		= FIO_SYNCIO | FIO_DISKLESSIO | FIO_NOIO,
109	.options		= options,
110	.option_struct_size	= sizeof(struct cpu_options),
111};
112
113static void fio_init fio_cpuio_register(void)
114{
115	register_ioengine(&ioengine);
116}
117
118static void fio_exit fio_cpuio_unregister(void)
119{
120	unregister_ioengine(&ioengine);
121}
122