From: Jens Axboe <jens.axboe@oracle.com>
Date: Thu, 28 Jan 2010 10:31:31 +0000 (+0100)
Subject: Add specific knob for controlling fallocate() usage
X-Git-Tag: fio-1.37~5
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=7bc8c2cf02fbd538ca388618ff2f4618787a86e0;hp=-c;ds=sidebyside

Add specific knob for controlling fallocate() usage

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

7bc8c2cf02fbd538ca388618ff2f4618787a86e0
diff --git a/HOWTO b/HOWTO
index 45a96bb1..91a1ec35 100644
--- a/HOWTO
+++ b/HOWTO
@@ -324,6 +324,11 @@ kb_base=int	The base unit for a kilobyte. The defacto base is 2^10, 1024.
 randrepeat=bool	For random IO workloads, seed the generator in a predictable
 		way so that results are repeatable across repetitions.
 
+fallocate=bool	By default, fio will use fallocate() to advise the system
+		of the size of the file we are going to write. This can be
+		turned off with fallocate=0. May not be available on all
+		supported platforms.
+
 fadvise_hint=bool By default, fio will use fadvise() to advise the kernel
 		on what IO patterns it is likely to issue. Sometimes you
 		want to test specific IO patterns without telling the
diff --git a/filesetup.c b/filesetup.c
index 70589aa5..cbef672e 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -64,6 +64,19 @@ static int extend_file(struct thread_data *td, struct fio_file *f)
 		return 1;
 	}
 
+#ifdef FIO_HAVE_FALLOCATE
+	if (td->o.fallocate && !td->o.fill_device) {
+		dprint(FD_FILE, "fallocate file %s size %llu\n", f->file_name,
+							f->real_file_size);
+
+		r = posix_fallocate(f->fd, 0, f->real_file_size);
+		if (r < 0) {
+			log_err("fio: posix_fallocate fails: %s\n",
+					strerror(-r));
+		}
+	}
+#endif
+	
 	if (!new_layout)
 		goto done;
 
@@ -78,16 +91,6 @@ static int extend_file(struct thread_data *td, struct fio_file *f)
 			td_verror(td, errno, "ftruncate");
 			goto err;
 		}
-
-#ifdef FIO_HAVE_FALLOCATE
-		dprint(FD_FILE, "fallocate file %s, size %llu\n", f->file_name,
-							f->real_file_size);
-		r = posix_fallocate(f->fd, 0, f->real_file_size);
-		if (r < 0) {
-			log_err("fio: posix_fallocate fails: %s\n",
-					strerror(-r));
-		}
-#endif
 	}
 
 	b = malloc(td->o.max_bs[DDIR_WRITE]);
diff --git a/fio.1 b/fio.1
index dfca43ef..60f787a1 100644
--- a/fio.1
+++ b/fio.1
@@ -182,6 +182,11 @@ reasons. Allow values are 1024 or 1000, with 1024 being the default.
 Seed the random number generator in a predictable way so results are repeatable
 across runs.  Default: true.
 .TP
+.BI fallocate \fR=\fPbool
+By default, fio will use fallocate() to advise the system of the size of the
+file we are going to write. This can be turned off with fallocate=0. May not
+be available on all supported platforms.
+.TP
 .BI fadvise_hint \fR=\fPbool
 Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
 are likely to be issued. Default: true.
diff --git a/fio.h b/fio.h
index 119dc09e..bdc17081 100644
--- a/fio.h
+++ b/fio.h
@@ -227,6 +227,7 @@ struct thread_options {
 	unsigned int file_service_type;
 	unsigned int group_reporting;
 	unsigned int fadvise_hint;
+	unsigned int fallocate;
 	unsigned int zero_buffers;
 	unsigned int refill_buffers;
 	unsigned int time_based;
diff --git a/options.c b/options.c
index 1543eb95..1c07982d 100644
--- a/options.c
+++ b/options.c
@@ -1081,6 +1081,15 @@ static struct fio_option options[] = {
 		},
 		.parent = "nrfiles",
 	},
+#ifdef FIO_HAVE_FALLOCATE
+	{
+		.name	= "fallocate",
+		.type	= FIO_OPT_BOOL,
+		.off1	= td_var_offset(fallocate),
+		.help	= "Use fallocate() when laying out files",
+		.def	= "1",
+	},
+#endif
 	{
 		.name	= "fadvise_hint",
 		.type	= FIO_OPT_BOOL,