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#include "../optgroup.h"
10
11struct cpu_options {
12	void *pad;
13	unsigned int cpuload;
14	unsigned int cpucycle;
15	unsigned int exit_io_done;
16};
17
18static struct fio_option options[] = {
19	{
20		.name	= "cpuload",
21		.lname	= "CPU load",
22		.type	= FIO_OPT_INT,
23		.off1	= offsetof(struct cpu_options, cpuload),
24		.help	= "Use this percentage of CPU",
25		.category = FIO_OPT_C_ENGINE,
26		.group	= FIO_OPT_G_INVALID,
27	},
28	{
29		.name	= "cpuchunks",
30		.lname	= "CPU chunk",
31		.type	= FIO_OPT_INT,
32		.off1	= offsetof(struct cpu_options, cpucycle),
33		.help	= "Length of the CPU burn cycles (usecs)",
34		.def	= "50000",
35		.parent = "cpuload",
36		.hide	= 1,
37		.category = FIO_OPT_C_ENGINE,
38		.group	= FIO_OPT_G_INVALID,
39	},
40	{
41		.name	= "exit_on_io_done",
42		.lname	= "Exit when IO threads are done",
43		.type	= FIO_OPT_BOOL,
44		.off1	= offsetof(struct cpu_options, exit_io_done),
45		.help	= "Exit when IO threads finish",
46		.def	= "0",
47		.category = FIO_OPT_C_ENGINE,
48		.group	= FIO_OPT_G_INVALID,
49	},
50	{
51		.name	= NULL,
52	},
53};
54
55
56static int fio_cpuio_queue(struct thread_data *td, struct io_u fio_unused *io_u)
57{
58	struct cpu_options *co = td->eo;
59
60	if (co->exit_io_done && !fio_running_or_pending_io_threads()) {
61		td->done = 1;
62		return FIO_Q_BUSY;
63	}
64
65	usec_spin(co->cpucycle);
66	return FIO_Q_COMPLETED;
67}
68
69static int fio_cpuio_init(struct thread_data *td)
70{
71	struct thread_options *o = &td->o;
72	struct cpu_options *co = td->eo;
73
74	if (!co->cpuload) {
75		td_vmsg(td, EINVAL, "cpu thread needs rate (cpuload=)","cpuio");
76		return 1;
77	}
78
79	if (co->cpuload > 100)
80		co->cpuload = 100;
81
82	/*
83	 * set thinktime_sleep and thinktime_spin appropriately
84	 */
85	o->thinktime_blocks = 1;
86	o->thinktime_spin = 0;
87	o->thinktime = (co->cpucycle * (100 - co->cpuload)) / co->cpuload;
88
89	o->nr_files = o->open_files = 1;
90
91	log_info("%s: ioengine=%s, cpuload=%u, cpucycle=%u\n",
92		td->o.name, td->io_ops->name, co->cpuload, co->cpucycle);
93
94	return 0;
95}
96
97static int fio_cpuio_open(struct thread_data fio_unused *td,
98			  struct fio_file fio_unused *f)
99{
100	return 0;
101}
102
103static struct ioengine_ops ioengine = {
104	.name		= "cpuio",
105	.version	= FIO_IOOPS_VERSION,
106	.queue		= fio_cpuio_queue,
107	.init		= fio_cpuio_init,
108	.open_file	= fio_cpuio_open,
109	.flags		= FIO_SYNCIO | FIO_DISKLESSIO | FIO_NOIO,
110	.options		= options,
111	.option_struct_size	= sizeof(struct cpu_options),
112};
113
114static void fio_init fio_cpuio_register(void)
115{
116	register_ioengine(&ioengine);
117}
118
119static void fio_exit fio_cpuio_unregister(void)
120{
121	unregister_ioengine(&ioengine);
122}
123