Turn the CPU burner into a real io engine
This removes the special casing in fio.c for the cpu engine, and
also gets rid of FIO_CPUIO.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index d1a3ad1..1374d05 100644
--- a/HOWTO
+++ b/HOWTO
@@ -301,6 +301,12 @@
or receive, if the latter only the port
argument is used.
+ cpu Doesn't transfer any data, but burns CPU
+ cycles according to the cpuload= and
+ cpucycle= options. Setting cpuload=85
+ will cause that job to do nothing but burn
+ 85% of the CPU.
+
external Prefix to specify loading an external
IO engine object file. Append the engine
filename, eg ioengine=external:/tmp/foo.o
diff --git a/README b/README
index 6980340..8b55f31 100644
--- a/README
+++ b/README
@@ -106,11 +106,11 @@
posixaio for POSIX aio, sync for regular read/write io,
mmap for mmap'ed io, syslet-rw for syslet driven
read/write, splice for using splice/vmsplice,
- sgio for direct SG_IO io, or net for network io. sgio
- only works on Linux on SCSI (or SCSI-like devices,
- such as usb-storage or sata/libata driven) devices.
- Fio also has a null io engine, which is mainly used
- for testing fio itself.
+ sgio for direct SG_IO io, net for network io, or cpuio
+ for a cycler burner load. sgio only works on Linux on
+ SCSI (or SCSI-like devices, such as usb-storage or
+ sata/libata driven) devices. Fio also has a null io
+ engine, which is mainly used for testing fio itself.
iodepth=x For async io, allow 'x' ios in flight
overwrite=x If 'x', layout a write file first.
nrfiles=x Spread io load over 'x' number of files per job,
@@ -176,7 +176,7 @@
ioscheduler=x Use ioscheduler 'x' for this job.
cpuload=x For a CPU io thread, percentage of CPU time to attempt
to burn.
- cpuchunks=x Split burn cycles into pieces of x.
+ cpuchunks=x Split burn cycles into pieces of x usecs.
Author
diff --git a/engines/cpu.c b/engines/cpu.c
index c89a4c9..7a084e0 100644
--- a/engines/cpu.c
+++ b/engines/cpu.c
@@ -1,30 +1,64 @@
#include "../fio.h"
#include "../os.h"
+static int fio_cpuio_queue(struct thread_data *td, struct io_u fio_unused *io_u)
+{
+ __usec_sleep(td->cpucycle);
+ return FIO_Q_COMPLETED;
+}
+
static int fio_cpuio_setup(struct thread_data fio_unused *td)
{
+ struct fio_file *f;
+ int i;
+
+ td->total_file_size = -1;
+ td->io_size = td->total_file_size;
+ td->total_io_size = td->io_size;
+
+ for_each_file(td, f, i) {
+ f->real_file_size = -1;
+ f->file_size = -1;
+ }
+
return 0;
}
static int fio_cpuio_init(struct thread_data *td)
{
if (!td->cpuload) {
- td_vmsg(td, EINVAL, "cpu thread needs rate", "cpu_load");
+ td_vmsg(td, EINVAL, "cpu thread needs rate (cpuload=)","cpuio");
return 1;
- } else if (td->cpuload > 100)
+ }
+
+ if (td->cpuload > 100)
td->cpuload = 100;
- td->nr_files = 0;
+ /*
+ * set thinktime_sleep and thinktime_spin appropriately
+ */
+ td->thinktime_blocks = 1;
+ td->thinktime_spin = 0;
+ td->thinktime = (td->cpucycle * (100 - td->cpuload)) / td->cpuload;
+ td->nr_files = td->open_files = 1;
+ return 0;
+}
+
+static int fio_cpuio_open(struct thread_data fio_unused *td, struct fio_file *f)
+{
+ f->fd = 0;
return 0;
}
static struct ioengine_ops ioengine = {
.name = "cpuio",
.version = FIO_IOOPS_VERSION,
+ .queue = fio_cpuio_queue,
.init = fio_cpuio_init,
.setup = fio_cpuio_setup,
- .flags = FIO_CPUIO,
+ .open_file = fio_cpuio_open,
+ .flags = FIO_SYNCIO | FIO_DISKLESSIO,
};
static void fio_init fio_cpuio_register(void)
diff --git a/fio.c b/fio.c
index 6ce46ba..36dde3a 100644
--- a/fio.c
+++ b/fio.c
@@ -362,31 +362,6 @@
}
/*
- * Not really an io thread, all it does is burn CPU cycles in the specified
- * manner.
- */
-static void do_cpuio(struct thread_data *td)
-{
- struct timeval e;
- int split = 100 / td->cpuload;
- int i = 0;
-
- while (!td->terminate) {
- fio_gettime(&e, NULL);
-
- if (runtime_exceeded(td, &e))
- break;
-
- if (!(i % split))
- __usec_sleep(10000);
- else
- usec_sleep(td, 10000);
-
- i++;
- }
-}
-
-/*
* Main IO worker function. It retrieves io_u's to process and queues
* and reaps them, checking for rate and errors along the way.
*/
@@ -566,9 +541,6 @@
int i, max_units;
char *p;
- if (td->io_ops->flags & FIO_CPUIO)
- return 0;
-
if (td->io_ops->flags & FIO_SYNCIO)
max_units = 1;
else
@@ -611,7 +583,7 @@
FILE *f;
int ret;
- if (td->io_ops->flags & FIO_CPUIO)
+ if (td->io_ops->flags & FIO_DISKLESSIO)
return 0;
sprintf(tmp, "%s/queue/scheduler", td->sysfs_root);
@@ -772,10 +744,7 @@
prune_io_piece_log(td);
- if (td->io_ops->flags & FIO_CPUIO)
- do_cpuio(td);
- else
- do_io(td);
+ do_io(td);
clear_state = 1;
@@ -878,7 +847,7 @@
* ->io_ops is NULL for a thread that has closed its
* io engine
*/
- if (td->io_ops && td->io_ops->flags & FIO_CPUIO)
+ if (td->io_ops && !strcmp(td->io_ops->name, "cpuio"))
cputhreads++;
if (!td->pid || td->runstate == TD_REAPED)
diff --git a/fio.h b/fio.h
index c20f21b..41a1790 100644
--- a/fio.h
+++ b/fio.h
@@ -212,9 +212,8 @@
enum fio_ioengine_flags {
FIO_SYNCIO = 1 << 0, /* io engine has synchronous ->queue */
- FIO_CPUIO = 1 << 1, /* cpu burner, doesn't do real io */
- FIO_RAWIO = 1 << 2, /* some sort of direct/raw io */
- FIO_DISKLESSIO = 1 << 3, /* no disk involved */
+ FIO_RAWIO = 1 << 1, /* some sort of direct/raw io */
+ FIO_DISKLESSIO = 1 << 2, /* no disk involved */
};
/*
diff --git a/init.c b/init.c
index 56df3c7..ba33a5e 100644
--- a/init.c
+++ b/init.c
@@ -102,6 +102,7 @@
#ifdef FIO_HAVE_SYSLET
{ .ival = "syslet-rw", },
#endif
+ { .ival = "cpuio", },
{ .ival = "external", },
},
},
@@ -474,7 +475,8 @@
.name = "cpuchunks",
.type = FIO_OPT_INT,
.off1 = td_var_offset(cpucycle),
- .help = "Length of the CPU burn cycles",
+ .help = "Length of the CPU burn cycles (usecs)",
+ .def = "50000",
},
#ifdef FIO_HAVE_CPU_AFFINITY
{
@@ -902,7 +904,7 @@
if (!terse_output) {
if (!job_add_num) {
- if (td->io_ops->flags & FIO_CPUIO)
+ if (!strcmp(td->io_ops->name, "cpuio"))
fprintf(f_out, "%s: ioengine=cpu, cpuload=%u, cpucycle=%u\n", td->name, td->cpuload, td->cpucycle);
else {
char *c1, *c2, *c3, *c4;
@@ -957,7 +959,7 @@
int fd, num_maps, blocks, i;
struct fio_file *f;
- if (td->io_ops->flags & FIO_CPUIO)
+ if (td->io_ops->flags & FIO_DISKLESSIO)
return 0;
fd = open("/dev/urandom", O_RDONLY);
diff --git a/ioengines.c b/ioengines.c
index 66991c7..9de7ca1 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -28,12 +28,6 @@
return 1;
}
- /*
- * cpu thread doesn't need to provide anything
- */
- if (ops->flags & FIO_CPUIO)
- return 0;
-
if (!ops->queue) {
log_err("%s: no queue handler\n", ops->name);
return 1;
diff --git a/log.c b/log.c
index 994f497..50caf3d 100644
--- a/log.c
+++ b/log.c
@@ -172,7 +172,7 @@
{
int ret = 0;
- if (td->io_ops->flags & FIO_CPUIO)
+ if (td->io_ops->flags & FIO_DISKLESSIO)
return 0;
if (td->read_iolog_file)