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
10 struct cpu_options {
11 void *pad;
12 unsigned int cpuload;
13 unsigned int cpucycle;
14 unsigned int exit_io_done;
15 };
16
17 static 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
fio_cpuio_queue(struct thread_data * td,struct io_u fio_unused * io_u)55 static 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
fio_cpuio_init(struct thread_data * td)68 static 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
fio_cpuio_open(struct thread_data fio_unused * td,struct fio_file fio_unused * f)96 static int fio_cpuio_open(struct thread_data fio_unused *td,
97 struct fio_file fio_unused *f)
98 {
99 return 0;
100 }
101
102 static 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
fio_cpuio_register(void)113 static void fio_init fio_cpuio_register(void)
114 {
115 register_ioengine(&ioengine);
116 }
117
fio_cpuio_unregister(void)118 static void fio_exit fio_cpuio_unregister(void)
119 {
120 unregister_ioengine(&ioengine);
121 }
122