Merge branch 'github_issue' of https://github.com/sitsofe/fio

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 2d8c7a0238fd20d77c1a1ee35e061ed16ab47cf8..7e46cee0eceac9f8d85c5b6191b3335dd72c2e14 100644 (file)
--- 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
 
@@ -2030,6 +2048,14 @@ I/O engine
                **nbd**
                        Read and write a Network Block Device (NBD).
 
+               **libcufile**
+                       I/O engine supporting libcufile synchronous access to nvidia-fs and a
+                       GPUDirect Storage-supported filesystem. This engine performs
+                       I/O without transferring buffers between user-space and the kernel,
+                       unless :option:`verify` is set or :option:`cuda_io` is `posix`.
+                       :option:`iomem` must not be `cudamalloc`. This ioengine defines
+                       engine specific options.
+
 I/O engine specific parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -2380,6 +2406,28 @@ with the caveat that when used on the command line, they must come after the
        nbd+unix:///?socket=/tmp/socket
        nbds://tlshost/exportname
 
+.. option:: gpu_dev_ids=str : [libcufile]
+
+       Specify the GPU IDs to use with CUDA. This is a colon-separated list of
+       int. GPUs are assigned to workers roundrobin. Default is 0.
+
+.. option:: cuda_io=str : [libcufile]
+
+       Specify the type of I/O to use with CUDA. Default is **cufile**.
+
+       **cufile**
+               Use libcufile and nvidia-fs. This option performs I/O directly
+               between a GPUDirect Storage filesystem and GPU buffers,
+               avoiding use of a bounce buffer. If :option:`verify` is set,
+               cudaMemcpy is used to copy verificaton data between RAM and GPU.
+               Verification data is copied from RAM to GPU before a write
+               and from GPU to RAM after a read. :option:`direct` must be 1.
+       **posix**
+               Use POSIX to perform I/O with a RAM buffer, and use cudaMemcpy
+               to transfer data between RAM and the GPUs. Data is copied from
+               GPU to RAM before a write and copied from RAM to GPU after a
+               read. :option:`verify` does not affect use of cudaMemcpy.
+
 I/O depth
 ~~~~~~~~~