[fio.git] / log.c

/*
 * Code related to writing an iolog of what a thread is doing, and to
 * later read that back and replay
 */
#include <stdio.h>
#include <stdlib.h>
#include <libgen.h>
#include <assert.h>
#include "flist.h"
#include "fio.h"

static const char iolog_ver2[] = "fio version 2 iolog";

void queue_io_piece(struct thread_data *td, struct io_piece *ipo)
{
	flist_add_tail(&ipo->list, &td->io_log_list);
	td->total_io_size += ipo->len;
}

void log_io_u(struct thread_data *td, struct io_u *io_u)
{
	const char *act[] = { "read", "write", "sync" };

	assert(io_u->ddir < 3);

	if (!td->o.write_iolog_file)
		return;

	fprintf(td->iolog_f, "%s %s %llu %lu\n", io_u->file->file_name,
						act[io_u->ddir], io_u->offset,
						io_u->buflen);
}

void log_file(struct thread_data *td, struct fio_file *f,
	      enum file_log_act what)
{
	const char *act[] = { "add", "open", "close" };

	assert(what < 3);

	if (!td->o.write_iolog_file)
		return;


	/*
	 * this happens on the pre-open/close done before the job starts
	 */
	if (!td->iolog_f)
		return;

	fprintf(td->iolog_f, "%s %s\n", f->file_name, act[what]);
}

static void iolog_delay(struct thread_data *td, unsigned long delay)
{
	unsigned long usec = utime_since_now(&td->last_issue);

	if (delay < usec)
		return;

	delay -= usec;

	/*
	 * less than 100 usec delay, just regard it as noise
	 */
	if (delay < 100)
		return;

	usec_sleep(td, delay);
}

static int ipo_special(struct thread_data *td, struct io_piece *ipo)
{
	struct fio_file *f;
	int ret;

	/*
	 * Not a special ipo
	 */
	if (ipo->ddir != DDIR_INVAL)
		return 0;

	f = td->files[ipo->fileno];

	switch (ipo->file_action) {
	case FIO_LOG_OPEN_FILE:
		ret = td_io_open_file(td, f);
		if (!ret) {
			free(ipo);
			break;
		}
		td_verror(td, ret, "iolog open file");
		return -1;
	case FIO_LOG_CLOSE_FILE:
		td_io_close_file(td, f);
		break;
	case FIO_LOG_UNLINK_FILE:
		unlink(f->file_name);
		break;
	default:
		log_err("fio: bad file action %d\n", ipo->file_action);
		break;
	}

	return 1;
}

int read_iolog_get(struct thread_data *td, struct io_u *io_u)
{
	struct io_piece *ipo;

	while (!flist_empty(&td->io_log_list)) {
		int ret;

		ipo = flist_entry(td->io_log_list.next, struct io_piece, list);
		flist_del(&ipo->list);

		ret = ipo_special(td, ipo);
		if (ret < 0) {
			free(ipo);
			break;
		} else if (ret > 0) {
			free(ipo);
			continue;
		}

		io_u->offset = ipo->offset;
		io_u->buflen = ipo->len;
		io_u->ddir = ipo->ddir;
		io_u->file = td->files[ipo->fileno];
		get_file(io_u->file);

		dprint(FD_IO, "iolog: get %llu/%lu/%s\n", io_u->offset,
					io_u->buflen, io_u->file->file_name);

		if (ipo->delay)
			iolog_delay(td, ipo->delay);

		free(ipo);
		return 0;
	}

	td->done = 1;
	return 1;
}

void prune_io_piece_log(struct thread_data *td)
{
	struct io_piece *ipo;
	struct rb_node *n;

	while ((n = rb_first(&td->io_hist_tree)) != NULL) {
		ipo = rb_entry(n, struct io_piece, rb_node);
		rb_erase(n, &td->io_hist_tree);
		free(ipo);
	}

	while (!flist_empty(&td->io_hist_list)) {
		ipo = flist_entry(td->io_hist_list.next, struct io_piece, list);
		flist_del(&ipo->list);
		free(ipo);
	}
}

/*
 * log a successful write, so we can unwind the log for verify
 */
void log_io_piece(struct thread_data *td, struct io_u *io_u)
{
	struct rb_node **p, *parent;
	struct io_piece *ipo, *__ipo;

	ipo = malloc(sizeof(struct io_piece));
	ipo->file = io_u->file;
	ipo->offset = io_u->offset;
	ipo->len = io_u->buflen;

	/*
	 * We don't need to sort the entries, if:
	 *
	 *	Sequential writes, or
	 *	Random writes that lay out the file as it goes along
	 *
	 * For both these cases, just reading back data in the order we
	 * wrote it out is the fastest.
	 */
	if (!td_random(td) || !td->o.overwrite) {
		INIT_FLIST_HEAD(&ipo->list);
		flist_add_tail(&ipo->list, &td->io_hist_list);
		return;
	}

	RB_CLEAR_NODE(&ipo->rb_node);
	p = &td->io_hist_tree.rb_node;
	parent = NULL;

	/*
	 * Sort the entry into the verification list
	 */
	while (*p) {
		parent = *p;

		__ipo = rb_entry(parent, struct io_piece, rb_node);
		if (ipo->offset <= __ipo->offset)
			p = &(*p)->rb_left;
		else
			p = &(*p)->rb_right;
	}

	rb_link_node(&ipo->rb_node, parent, p);
	rb_insert_color(&ipo->rb_node, &td->io_hist_tree);
}

void write_iolog_close(struct thread_data *td)
{
	fflush(td->iolog_f);
	fclose(td->iolog_f);
	free(td->iolog_buf);
	td->iolog_f = NULL;
	td->iolog_buf = NULL;
}

/*
 * Read version 2 iolog data. It is enhanced to include per-file logging,
 * syncs, etc.
 */
static int read_iolog2(struct thread_data *td, FILE *f)
{
	unsigned long long offset;
	unsigned int bytes;
	int reads, writes, fileno = 0, file_action = 0; /* stupid gcc */
	char *fname, *act;
	char *str, *p;
	enum fio_ddir rw;

	free_release_files(td);

	/*
	 * Read in the read iolog and store it, reuse the infrastructure
	 * for doing verifications.
	 */
	str = malloc(4096);
	fname = malloc(256+16);
	act = malloc(256+16);

	reads = writes = 0;
	while ((p = fgets(str, 4096, f)) != NULL) {
		struct io_piece *ipo;
		int r;

		r = sscanf(p, "%256s %256s %llu %u", fname, act, &offset,
									&bytes);
		if (r == 4) {
			/*
			 * Check action first
			 */
			if (!strcmp(act, "read"))
				rw = DDIR_READ;
			else if (!strcmp(act, "write"))
				rw = DDIR_WRITE;
			else if (!strcmp(act, "sync"))
				rw = DDIR_SYNC;
			else {
				log_err("fio: bad iolog file action: %s\n",
									act);
				continue;
			}
		} else if (r == 2) {
			rw = DDIR_INVAL;
			if (!strcmp(act, "add")) {
				td->o.nr_files++;
				fileno = add_file(td, fname);
				file_action = FIO_LOG_ADD_FILE;
				continue;
			} else if (!strcmp(act, "open")) {
				fileno = get_fileno(td, fname);
				file_action = FIO_LOG_OPEN_FILE;
			} else if (!strcmp(act, "close")) {
				fileno = get_fileno(td, fname);
				file_action = FIO_LOG_CLOSE_FILE;
			} else {
				log_err("fio: bad iolog file action: %s\n",
									act);
				continue;
			}
		} else {
			log_err("bad iolog2: %s", p);
			continue;
		}

		if (rw == DDIR_READ)
			reads++;
		else if (rw == DDIR_WRITE) {
			/*
			 * Don't add a write for ro mode
			 */
			if (read_only)
				continue;
			writes++;
		} else if (rw != DDIR_SYNC && rw != DDIR_INVAL) {
			log_err("bad ddir: %d\n", rw);
			continue;
		}

		/*
		 * Make note of file
		 */
		ipo = malloc(sizeof(*ipo));
		memset(ipo, 0, sizeof(*ipo));
		INIT_FLIST_HEAD(&ipo->list);
		ipo->offset = offset;
		ipo->len = bytes;
		ipo->ddir = rw;
		if (bytes > td->o.max_bs[rw])
			td->o.max_bs[rw] = bytes;
		if (rw == DDIR_INVAL) {
			ipo->fileno = fileno;
			ipo->file_action = file_action;
		}
		queue_io_piece(td, ipo);
	}

	free(str);
	free(act);
	free(fname);

	if (writes && read_only) {
		log_err("fio: <%s> skips replay of %d writes due to"
			" read-only\n", td->o.name, writes);
		writes = 0;
	}

	if (!reads && !writes)
		return 1;
	else if (reads && !writes)
		td->o.td_ddir = TD_DDIR_READ;
	else if (!reads && writes)
		td->o.td_ddir = TD_DDIR_WRITE;
	else
		td->o.td_ddir = TD_DDIR_RW;

	return 0;
}

/*
 * open iolog, check version, and call appropriate parser
 */
static int init_iolog_read(struct thread_data *td)
{
	char buffer[256], *p;
	FILE *f;
	int ret;

	f = fopen(td->o.read_iolog_file, "r");
	if (!f) {
		perror("fopen read iolog");
		return 1;
	}

	p = fgets(buffer, sizeof(buffer), f);
	if (!p) {
		td_verror(td, errno, "iolog read");
		log_err("fio: unable to read iolog\n");
		return 1;
	}

	/*
	 * version 2 of the iolog stores a specific string as the
	 * first line, check for that
	 */
	if (!strncmp(iolog_ver2, buffer, strlen(iolog_ver2)))
		ret = read_iolog2(td, f);
	else {
		log_err("fio: iolog version 1 is no longer supported\n");
		ret = 1;
	}

	fclose(f);
	return ret;
}

/*
 * Setup a log for storing io patterns.
 */
static int init_iolog_write(struct thread_data *td)
{
	struct fio_file *ff;
	FILE *f;
	unsigned int i;

	f = fopen(td->o.write_iolog_file, "w+");
	if (!f) {
		perror("fopen write iolog");
		return 1;
	}

	/*
	 * That's it for writing, setup a log buffer and we're done.
	  */
	td->iolog_f = f;
	td->iolog_buf = malloc(8192);
	setvbuf(f, td->iolog_buf, _IOFBF, 8192);

	/*
	 * write our version line
	 */
	if (fprintf(f, "%s\n", iolog_ver2) < 0) {
		perror("iolog init\n");
		return 1;
	}

	/*
	 * add all known files
	 */
	for_each_file(td, ff, i)
		log_file(td, ff, FIO_LOG_ADD_FILE);

	return 0;
}

int init_iolog(struct thread_data *td)
{
	int ret = 0;

	if (td->io_ops->flags & FIO_DISKLESSIO)
		return 0;

	if (td->o.read_iolog_file) {
		/*
		 * Check if it's a blktrace file and load that if possible.
		 * Otherwise assume it's a normal log file and load that.
		 */
		if (is_blktrace(td->o.read_iolog_file))
			ret = load_blktrace(td, td->o.read_iolog_file);
		else
			ret = init_iolog_read(td);
	} else if (td->o.write_iolog_file)
		ret = init_iolog_write(td);

	return ret;
}

void setup_log(struct io_log **log)
{
	struct io_log *l = malloc(sizeof(*l));

	l->nr_samples = 0;
	l->max_samples = 1024;
	l->log = malloc(l->max_samples * sizeof(struct io_sample));
	*log = l;
}

void __finish_log(struct io_log *log, const char *name)
{
	unsigned int i;
	FILE *f;

	f = fopen(name, "w");
	if (!f) {
		perror("fopen log");
		return;
	}

	for (i = 0; i < log->nr_samples; i++) {
		fprintf(f, "%lu, %lu, %u\n", log->log[i].time, log->log[i].val,
						log->log[i].ddir);
	}

	fclose(f);
	free(log->log);
	free(log);
}

void finish_log(struct thread_data *td, struct io_log *log, const char *name)
{
	char file_name[256], *p;

	snprintf(file_name, 200, "%s_%s.log", td->o.name, name);
	p = basename(file_name);
	__finish_log(log, p);
}
Commit	Line	Data
	1	/*
	2	* Code related to writing an iolog of what a thread is doing, and to
	3	* later read that back and replay
	4	*/
	5	#include <stdio.h>
	6	#include <stdlib.h>
	7	#include <libgen.h>
	8	#include <assert.h>
	9	#include "flist.h"
	10	#include "fio.h"
	11
	12	static const char iolog_ver2[] = "fio version 2 iolog";
	13
	14	void queue_io_piece(struct thread_data td, struct io_piece ipo)
	15	{
	16	flist_add_tail(&ipo->list, &td->io_log_list);
	17	td->total_io_size += ipo->len;
	18	}
	19
	20	void log_io_u(struct thread_data td, struct io_u io_u)
	21	{
	22	const char *act[] = { "read", "write", "sync" };
	23
	24	assert(io_u->ddir < 3);
	25
	26	if (!td->o.write_iolog_file)
	27	return;
	28
	29	fprintf(td->iolog_f, "%s %s %llu %lu\n", io_u->file->file_name,
	30	act[io_u->ddir], io_u->offset,
	31	io_u->buflen);
	32	}
	33
	34	void log_file(struct thread_data td, struct fio_file f,
	35	enum file_log_act what)
	36	{
	37	const char *act[] = { "add", "open", "close" };
	38
	39	assert(what < 3);
	40
	41	if (!td->o.write_iolog_file)
	42	return;
	43
	44
	45	/*
	46	* this happens on the pre-open/close done before the job starts
	47	*/
	48	if (!td->iolog_f)
	49	return;
	50
	51	fprintf(td->iolog_f, "%s %s\n", f->file_name, act[what]);
	52	}
	53
	54	static void iolog_delay(struct thread_data *td, unsigned long delay)
	55	{
	56	unsigned long usec = utime_since_now(&td->last_issue);
	57
	58	if (delay < usec)
	59	return;
	60
	61	delay -= usec;
	62
	63	/*
	64	* less than 100 usec delay, just regard it as noise
	65	*/
	66	if (delay < 100)
	67	return;
	68
	69	usec_sleep(td, delay);
	70	}
	71
	72	static int ipo_special(struct thread_data td, struct io_piece ipo)
	73	{
	74	struct fio_file *f;
	75	int ret;
	76
	77	/*
	78	* Not a special ipo
	79	*/
	80	if (ipo->ddir != DDIR_INVAL)
	81	return 0;
	82
	83	f = td->files[ipo->fileno];
	84
	85	switch (ipo->file_action) {
	86	case FIO_LOG_OPEN_FILE:
	87	ret = td_io_open_file(td, f);
	88	if (!ret) {
	89	free(ipo);
	90	break;
	91	}
	92	td_verror(td, ret, "iolog open file");
	93	return -1;
	94	case FIO_LOG_CLOSE_FILE:
	95	td_io_close_file(td, f);
	96	break;
	97	case FIO_LOG_UNLINK_FILE:
	98	unlink(f->file_name);
	99	break;
	100	default:
	101	log_err("fio: bad file action %d\n", ipo->file_action);
	102	break;
	103	}
	104
	105	return 1;
	106	}
	107
	108	int read_iolog_get(struct thread_data td, struct io_u io_u)
	109	{
	110	struct io_piece *ipo;
	111
	112	while (!flist_empty(&td->io_log_list)) {
	113	int ret;
	114
	115	ipo = flist_entry(td->io_log_list.next, struct io_piece, list);
	116	flist_del(&ipo->list);
	117
	118	ret = ipo_special(td, ipo);
	119	if (ret < 0) {
	120	free(ipo);
	121	break;
	122	} else if (ret > 0) {
	123	free(ipo);
	124	continue;
	125	}
	126
	127	io_u->offset = ipo->offset;
	128	io_u->buflen = ipo->len;
	129	io_u->ddir = ipo->ddir;
	130	io_u->file = td->files[ipo->fileno];
	131	get_file(io_u->file);
	132
	133	dprint(FD_IO, "iolog: get %llu/%lu/%s\n", io_u->offset,
	134	io_u->buflen, io_u->file->file_name);
	135
	136	if (ipo->delay)
	137	iolog_delay(td, ipo->delay);
	138
	139	free(ipo);
	140	return 0;
	141	}
	142
	143	td->done = 1;
	144	return 1;
	145	}
	146
	147	void prune_io_piece_log(struct thread_data *td)
	148	{
	149	struct io_piece *ipo;
	150	struct rb_node *n;
	151
	152	while ((n = rb_first(&td->io_hist_tree)) != NULL) {
	153	ipo = rb_entry(n, struct io_piece, rb_node);
	154	rb_erase(n, &td->io_hist_tree);
	155	free(ipo);
	156	}
	157
	158	while (!flist_empty(&td->io_hist_list)) {
	159	ipo = flist_entry(td->io_hist_list.next, struct io_piece, list);
	160	flist_del(&ipo->list);
	161	free(ipo);
	162	}
	163	}
	164
	165	/*
	166	* log a successful write, so we can unwind the log for verify
	167	*/
	168	void log_io_piece(struct thread_data td, struct io_u io_u)
	169	{
	170	struct rb_node *p, parent;
	171	struct io_piece ipo, __ipo;
	172
	173	ipo = malloc(sizeof(struct io_piece));
	174	ipo->file = io_u->file;
	175	ipo->offset = io_u->offset;
	176	ipo->len = io_u->buflen;
	177
	178	/*
	179	* We don't need to sort the entries, if:
	180	*
	181	* Sequential writes, or
	182	* Random writes that lay out the file as it goes along
	183	*
	184	* For both these cases, just reading back data in the order we
	185	* wrote it out is the fastest.
	186	*/
	187	if (!td_random(td) \|\| !td->o.overwrite) {
	188	INIT_FLIST_HEAD(&ipo->list);
	189	flist_add_tail(&ipo->list, &td->io_hist_list);
	190	return;
	191	}
	192
	193	RB_CLEAR_NODE(&ipo->rb_node);
	194	p = &td->io_hist_tree.rb_node;
	195	parent = NULL;
	196
	197	/*
	198	* Sort the entry into the verification list
	199	*/
	200	while (*p) {
	201	parent = *p;
	202
	203	__ipo = rb_entry(parent, struct io_piece, rb_node);
	204	if (ipo->offset <= __ipo->offset)
	205	p = &(*p)->rb_left;
	206	else
	207	p = &(*p)->rb_right;
	208	}
	209
	210	rb_link_node(&ipo->rb_node, parent, p);
	211	rb_insert_color(&ipo->rb_node, &td->io_hist_tree);
	212	}
	213
	214	void write_iolog_close(struct thread_data *td)
	215	{
	216	fflush(td->iolog_f);
	217	fclose(td->iolog_f);
	218	free(td->iolog_buf);
	219	td->iolog_f = NULL;
	220	td->iolog_buf = NULL;
	221	}
	222
	223	/*
	224	* Read version 2 iolog data. It is enhanced to include per-file logging,
	225	* syncs, etc.
	226	*/
	227	static int read_iolog2(struct thread_data td, FILE f)
	228	{
	229	unsigned long long offset;
	230	unsigned int bytes;
	231	int reads, writes, fileno = 0, file_action = 0; /* stupid gcc */
	232	char fname, act;
	233	char str, p;
	234	enum fio_ddir rw;
	235
	236	free_release_files(td);
	237
	238	/*
	239	* Read in the read iolog and store it, reuse the infrastructure
	240	* for doing verifications.
	241	*/
	242	str = malloc(4096);
	243	fname = malloc(256+16);
	244	act = malloc(256+16);
	245
	246	reads = writes = 0;
	247	while ((p = fgets(str, 4096, f)) != NULL) {
	248	struct io_piece *ipo;
	249	int r;
	250
	251	r = sscanf(p, "%256s %256s %llu %u", fname, act, &offset,
	252	&bytes);
	253	if (r == 4) {
	254	/*
	255	* Check action first
	256	*/
	257	if (!strcmp(act, "read"))
	258	rw = DDIR_READ;
	259	else if (!strcmp(act, "write"))
	260	rw = DDIR_WRITE;
	261	else if (!strcmp(act, "sync"))
	262	rw = DDIR_SYNC;
	263	else {
	264	log_err("fio: bad iolog file action: %s\n",
	265	act);
	266	continue;
	267	}
	268	} else if (r == 2) {
	269	rw = DDIR_INVAL;
	270	if (!strcmp(act, "add")) {
	271	td->o.nr_files++;
	272	fileno = add_file(td, fname);
	273	file_action = FIO_LOG_ADD_FILE;
	274	continue;
	275	} else if (!strcmp(act, "open")) {
	276	fileno = get_fileno(td, fname);
	277	file_action = FIO_LOG_OPEN_FILE;
	278	} else if (!strcmp(act, "close")) {
	279	fileno = get_fileno(td, fname);
	280	file_action = FIO_LOG_CLOSE_FILE;
	281	} else {
	282	log_err("fio: bad iolog file action: %s\n",
	283	act);
	284	continue;
	285	}
	286	} else {
	287	log_err("bad iolog2: %s", p);
	288	continue;
	289	}
	290
	291	if (rw == DDIR_READ)
	292	reads++;
	293	else if (rw == DDIR_WRITE) {
	294	/*
	295	* Don't add a write for ro mode
	296	*/
	297	if (read_only)
	298	continue;
	299	writes++;
	300	} else if (rw != DDIR_SYNC && rw != DDIR_INVAL) {
	301	log_err("bad ddir: %d\n", rw);
	302	continue;
	303	}
	304
	305	/*
	306	* Make note of file
	307	*/
	308	ipo = malloc(sizeof(*ipo));
	309	memset(ipo, 0, sizeof(*ipo));
	310	INIT_FLIST_HEAD(&ipo->list);
	311	ipo->offset = offset;
	312	ipo->len = bytes;
	313	ipo->ddir = rw;
	314	if (bytes > td->o.max_bs[rw])
	315	td->o.max_bs[rw] = bytes;
	316	if (rw == DDIR_INVAL) {
	317	ipo->fileno = fileno;
	318	ipo->file_action = file_action;
	319	}
	320	queue_io_piece(td, ipo);
	321	}
	322
	323	free(str);
	324	free(act);
	325	free(fname);
	326
	327	if (writes && read_only) {
	328	log_err("fio: <%s> skips replay of %d writes due to"
	329	" read-only\n", td->o.name, writes);
	330	writes = 0;
	331	}
	332
	333	if (!reads && !writes)
	334	return 1;
	335	else if (reads && !writes)
	336	td->o.td_ddir = TD_DDIR_READ;
	337	else if (!reads && writes)
	338	td->o.td_ddir = TD_DDIR_WRITE;
	339	else
	340	td->o.td_ddir = TD_DDIR_RW;
	341
	342	return 0;
	343	}
	344
	345	/*
	346	* open iolog, check version, and call appropriate parser
	347	*/
	348	static int init_iolog_read(struct thread_data *td)
	349	{
	350	char buffer[256], *p;
	351	FILE *f;
	352	int ret;
	353
	354	f = fopen(td->o.read_iolog_file, "r");
	355	if (!f) {
	356	perror("fopen read iolog");
	357	return 1;
	358	}
	359
	360	p = fgets(buffer, sizeof(buffer), f);
	361	if (!p) {
	362	td_verror(td, errno, "iolog read");
	363	log_err("fio: unable to read iolog\n");
	364	return 1;
	365	}
	366
	367	/*
	368	* version 2 of the iolog stores a specific string as the
	369	* first line, check for that
	370	*/
	371	if (!strncmp(iolog_ver2, buffer, strlen(iolog_ver2)))
	372	ret = read_iolog2(td, f);
	373	else {
	374	log_err("fio: iolog version 1 is no longer supported\n");
	375	ret = 1;
	376	}
	377
	378	fclose(f);
	379	return ret;
	380	}
	381
	382	/*
	383	* Setup a log for storing io patterns.
	384	*/
	385	static int init_iolog_write(struct thread_data *td)
	386	{
	387	struct fio_file *ff;
	388	FILE *f;
	389	unsigned int i;
	390
	391	f = fopen(td->o.write_iolog_file, "w+");
	392	if (!f) {
	393	perror("fopen write iolog");
	394	return 1;
	395	}
	396
	397	/*
	398	* That's it for writing, setup a log buffer and we're done.
	399	*/
	400	td->iolog_f = f;
	401	td->iolog_buf = malloc(8192);
	402	setvbuf(f, td->iolog_buf, _IOFBF, 8192);
	403
	404	/*
	405	* write our version line
	406	*/
	407	if (fprintf(f, "%s\n", iolog_ver2) < 0) {
	408	perror("iolog init\n");
	409	return 1;
	410	}
	411
	412	/*
	413	* add all known files
	414	*/
	415	for_each_file(td, ff, i)
	416	log_file(td, ff, FIO_LOG_ADD_FILE);
	417
	418	return 0;
	419	}
	420
	421	int init_iolog(struct thread_data *td)
	422	{
	423	int ret = 0;
	424
	425	if (td->io_ops->flags & FIO_DISKLESSIO)
	426	return 0;
	427
	428	if (td->o.read_iolog_file) {
	429	/*
	430	* Check if it's a blktrace file and load that if possible.
	431	* Otherwise assume it's a normal log file and load that.
	432	*/
	433	if (is_blktrace(td->o.read_iolog_file))
	434	ret = load_blktrace(td, td->o.read_iolog_file);
	435	else
	436	ret = init_iolog_read(td);
	437	} else if (td->o.write_iolog_file)
	438	ret = init_iolog_write(td);
	439
	440	return ret;
	441	}
	442
	443	void setup_log(struct io_log **log)
	444	{
	445	struct io_log l = malloc(sizeof(l));
	446
	447	l->nr_samples = 0;
	448	l->max_samples = 1024;
	449	l->log = malloc(l->max_samples * sizeof(struct io_sample));
	450	*log = l;
	451	}
	452
	453	void __finish_log(struct io_log log, const char name)
	454	{
	455	unsigned int i;
	456	FILE *f;
	457
	458	f = fopen(name, "w");
	459	if (!f) {
	460	perror("fopen log");
	461	return;
	462	}
	463
	464	for (i = 0; i < log->nr_samples; i++) {
	465	fprintf(f, "%lu, %lu, %u\n", log->log[i].time, log->log[i].val,
	466	log->log[i].ddir);
	467	}
	468
	469	fclose(f);
	470	free(log->log);
	471	free(log);
	472	}
	473
	474	void finish_log(struct thread_data td, struct io_log log, const char *name)
	475	{
	476	char file_name[256], *p;
	477
	478	snprintf(file_name, 200, "%s_%s.log", td->o.name, name);
	479	p = basename(file_name);
	480	__finish_log(log, p);
	481	}