X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=386fd12aa7b14b80405a4df2851b3c0f7e967fd0;hp=d8586723a281ae8418687fd2561a3f4b6ecaee26;hb=9107a641e67f27003fa6cbe7b55b1ec6a0239197;hpb=be23e6be4fadb723f925824f88fbaedbd3502251

diff --git a/HOWTO b/HOWTO
index d8586723..386fd12a 100644
--- a/HOWTO
+++ b/HOWTO
@@ -1677,10 +1677,28 @@ Buffers and memory
 	This will be ignored if :option:`pre_read` is also specified for the
 	same job.
 
-.. option:: sync=bool
+.. option:: sync=str
+
+	Whether, and what type, of synchronous I/O to use for writes.  The allowed
+	values are:
+
+		**none**
+			Do not use synchronous IO, the default.
+
+		**0**
+			Same as **none**.
+
+		**sync**
+			Use synchronous file IO. For the majority of I/O engines,
+			this means using O_SYNC.
+
+		**1**
+			Same as **sync**.
+
+		**dsync**
+			Use synchronous data IO. For the majority of I/O engines,
+			this means using O_DSYNC.
 
-	Use synchronous I/O for buffered writes. For the majority of I/O engines,
-	this means using O_SYNC. Default: false.
 
 .. option:: iomem=str, mem=str
 
@@ -2474,7 +2492,8 @@ I/O depth
 	can increase latencies. The benefit is that fio can manage submission rates
 	independently of the device completion rates. This avoids skewed latency
 	reporting if I/O gets backed up on the device side (the coordinated omission
-	problem).
+	problem). Note that this option cannot reliably be used with async IO
+	engines.
 
 
 I/O rate