fio: support io_size=N% (N <= 100)

Parse "io_size=N%".

Semantics is "multiply whatever size= calculations result in".

Example #1:

	size=50%
	io_size=50%

will do 25% of a file.

Example #2:

	size=1G
	io_size=50%

will do 512M I/O.

As side effect, fix a bug with essentially infinite loop if both size=N%
and io_size=M% are given: io_size is set to 2^64-... in this case (a lot!).

Note: only values under 100% work currently.
Going for io_size=150% requires resetting workload generator state
which is whole separate endeavour.

Signed-off-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

cconv.c

@@ -102,6 +102,7 @@ void convert_thread_options_to_cpu(struct thread_options *o,
 	o->size = le64_to_cpu(top->size);
 	o->io_size = le64_to_cpu(top->io_size);
 	o->size_percent = le32_to_cpu(top->size_percent);
+	o->io_size_percent = le32_to_cpu(top->io_size_percent);
 	o->fill_device = le32_to_cpu(top->fill_device);
 	o->file_append = le32_to_cpu(top->file_append);
 	o->file_size_low = le64_to_cpu(top->file_size_low);
@@ -367,6 +368,7 @@ void convert_thread_options_to_net(struct thread_options_pack *top,
 	top->iodepth_batch_complete_max = cpu_to_le32(o->iodepth_batch_complete_max);
 	top->serialize_overlap = cpu_to_le32(o->serialize_overlap);
 	top->size_percent = cpu_to_le32(o->size_percent);
+	top->io_size_percent = cpu_to_le32(o->io_size_percent);
 	top->fill_device = cpu_to_le32(o->fill_device);
 	top->file_append = cpu_to_le32(o->file_append);
 	top->ratecycle = cpu_to_le32(o->ratecycle);

filesetup.c

@@ -1139,6 +1139,8 @@ int setup_files(struct thread_data *td)
 		if (f->io_size == -1ULL)
 			total_size = -1ULL;
 		else {
+			uint64_t io_size;
+
                         if (o->size_percent && o->size_percent != 100) {
 				uint64_t file_size;
 
@@ -1150,7 +1152,14 @@ int setup_files(struct thread_data *td)
 
 				f->io_size -= (f->io_size % td_min_bs(td));
 			}
-			total_size += f->io_size;
+
+			io_size = f->io_size;
+			if (o->io_size_percent && o->io_size_percent != 100) {
+				io_size *= o->io_size_percent;
+				io_size /= 100;
+			}
+
+			total_size += io_size;
 		}
 
 		if (f->filetype == FIO_TYPE_FILE &&

options.c

@@ -1476,6 +1476,22 @@ static int str_size_cb(void *data, unsigned long long *__val)
 	return 0;
 }
 
+static int str_io_size_cb(void *data, unsigned long long *__val)
+{
+	struct thread_data *td = cb_data_to_td(data);
+	unsigned long long v = *__val;
+
+	if (parse_is_percent(v)) {
+		td->o.io_size = 0;
+		td->o.io_size_percent = -1ULL - v;
+		dprint(FD_PARSE, "SET io_size_percent %d\n",
+					td->o.io_size_percent);
+	} else
+		td->o.io_size = v;
+
+	return 0;
+}
+
 static int str_write_bw_log_cb(void *data, const char *str)
 {
 	struct thread_data *td = cb_data_to_td(data);
@@ -2043,6 +2059,7 @@ struct fio_option fio_options[FIO_MAX_OPTS] = {
 		.alias	= "io_limit",
 		.lname	= "IO Size",
 		.type	= FIO_OPT_STR_VAL,
+		.cb	= str_io_size_cb,
 		.off1	= offsetof(struct thread_options, io_size),
 		.help	= "Total size of I/O to be performed",
 		.interval = 1024 * 1024,

server.h

@@ -48,7 +48,7 @@ struct fio_net_cmd_reply {
 };
 
 enum {
-	FIO_SERVER_VER			= 85,
+	FIO_SERVER_VER			= 86,
 
 	FIO_SERVER_MAX_FRAGMENT_PDU	= 1024,
 	FIO_SERVER_MAX_CMD_MB		= 2048,

thread_options.h

@@ -83,6 +83,7 @@ struct thread_options {
 	unsigned long long size;
 	unsigned long long io_size;
 	unsigned int size_percent;
+	unsigned int io_size_percent;
 	unsigned int fill_device;
 	unsigned int file_append;
 	unsigned long long file_size_low;
@@ -381,6 +382,7 @@ struct thread_options_pack {
 	uint64_t size;
 	uint64_t io_size;
 	uint32_t size_percent;
+	uint32_t io_size_percent;
 	uint32_t fill_device;
 	uint32_t file_append;
 	uint32_t unique_filename;
@@ -460,6 +462,8 @@ struct thread_options_pack {
 	struct zone_split zone_split[DDIR_RWDIR_CNT][ZONESPLIT_MAX];
 	uint32_t zone_split_nr[DDIR_RWDIR_CNT];
 
+	uint8_t pad1[4];
+
 	fio_fp64_t zipf_theta;
 	fio_fp64_t pareto_h;
 	fio_fp64_t gauss_dev;