From: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Date: Wed, 20 May 2009 09:30:55 +0000 (+0200)
Subject: Add pre_read option
X-Git-Tag: fio-1.26.3~3
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=afad68f778a764cbe57d4a5d54cbea32444aaa45

Add pre_read option

With this option set, files will be pre-read into memory before
starting the given IO operation(s).

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/HOWTO b/HOWTO
index 9bfa4378..1390f386 100644
--- a/HOWTO
+++ b/HOWTO
@@ -713,6 +713,9 @@ create_fsync=bool	fsync the data file after creation. This is the
 create_on_open=bool	Don't pre-setup the files for IO, just create open()
 			when it's time to do IO to that file.
 
+pre_read=bool	If this is given, files will be pre-read into memory before
+		starting the given IO operation.
+
 unlink=bool	Unlink the job files when done. Not the default, as repeated
 		runs of that job would then waste time recreating the file
 		set again and again.
diff --git a/filesetup.c b/filesetup.c
index 04d7b987..28580188 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -119,6 +119,39 @@ err:
 	return 1;
 }
 
+static int pre_read_file(struct thread_data *td, struct fio_file *f)
+{
+	int r;
+	unsigned long long left;
+	unsigned int bs;
+	char *b;
+
+	bs = td->o.max_bs[DDIR_READ];
+	b = malloc(bs);
+	memset(b, 0, bs);
+
+	lseek(f->fd, f->file_offset, SEEK_SET);
+	left = f->io_size;
+
+	while (left && !td->terminate) {
+		if (bs > left)
+			bs = left;
+
+		r = read(f->fd, b, bs);
+
+		if (r == (int) bs) {
+			left -= bs;
+			continue;
+		} else {
+			td_verror(td, EIO, "pre_read");
+			break;
+		}
+	}
+
+	free(b);
+	return 0;
+}
+
 static unsigned long long get_rand_file_size(struct thread_data *td)
 {
 	unsigned long long ret, sized;
@@ -572,6 +605,20 @@ err_offset:
 	return 1;
 }
 
+int pre_read_files(struct thread_data *td)
+{
+	struct fio_file *f;
+	unsigned int i;
+
+	dprint(FD_FILE, "pre_read files\n");
+
+	for_each_file(td, f, i) {
+		pre_read_file(td, f);
+	}
+
+	return 1;
+}
+
 int init_random_map(struct thread_data *td)
 {
 	unsigned long long blocks, num_maps;
diff --git a/fio.c b/fio.c
index 4a02f2eb..185f99a7 100644
--- a/fio.c
+++ b/fio.c
@@ -1018,6 +1018,11 @@ static void *thread_main(void *data)
 			goto err;
 	}
 
+	if (td->o.pre_read) {
+		if (pre_read_files(td) < 0)
+			goto err;
+	}
+
 	fio_gettime(&td->epoch, NULL);
 	getrusage(RUSAGE_SELF, &td->ts.ru_start);
 
diff --git a/fio.h b/fio.h
index 1ccc862e..cb80a111 100644
--- a/fio.h
+++ b/fio.h
@@ -447,6 +447,7 @@ struct thread_options {
 	unsigned int create_fsync;
 	unsigned int create_on_open;
 	unsigned int end_fsync;
+	unsigned int pre_read;
 	unsigned int sync_io;
 	unsigned int verify;
 	unsigned int do_verify;
@@ -874,6 +875,7 @@ extern int __must_check file_invalidate_cache(struct thread_data *, struct fio_f
 extern int __must_check generic_open_file(struct thread_data *, struct fio_file *);
 extern int __must_check generic_close_file(struct thread_data *, struct fio_file *);
 extern int __must_check generic_get_file_size(struct thread_data *, struct fio_file *);
+extern int __must_check pre_read_files(struct thread_data *);
 extern int add_file(struct thread_data *, const char *);
 extern void get_file(struct fio_file *);
 extern int __must_check put_file(struct thread_data *, struct fio_file *);
diff --git a/options.c b/options.c
index 9267f790..a45d1af6 100644
--- a/options.c
+++ b/options.c
@@ -1334,6 +1334,13 @@ static struct fio_option options[] = {
 		.help	= "Create files when they are opened for IO",
 		.def	= "0",
 	},
+ 	{
+		.name	= "pre_read",
+		.type	= FIO_OPT_BOOL,
+		.off1	= td_var_offset(pre_read),
+		.help	= "Preread files before starting official testing",
+		.def	= "0",
+	},
 	{
 		.name	= "cpuload",
 		.type	= FIO_OPT_INT,