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
11 struct cpu_options {
12 void *pad;
13 unsigned int cpuload;
14 unsigned int cpucycle;
15 unsigned int exit_io_done;
16 };
17
18 static 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
fio_cpuio_queue(struct thread_data * td,struct io_u fio_unused * io_u)56 static 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
fio_cpuio_init(struct thread_data * td)69 static 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
fio_cpuio_open(struct thread_data fio_unused * td,struct fio_file fio_unused * f)97 static int fio_cpuio_open(struct thread_data fio_unused *td,
98 struct fio_file fio_unused *f)
99 {
100 return 0;
101 }
102
103 static 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
fio_cpuio_register(void)114 static void fio_init fio_cpuio_register(void)
115 {
116 register_ioengine(&ioengine);
117 }
118
fio_cpuio_unregister(void)119 static void fio_exit fio_cpuio_unregister(void)
120 {
121 unregister_ioengine(&ioengine);
122 }
123