[PATCH] doc: add dma perf feature details

[Amit Prakash Shukla <amitprakashs@marvell.com>]

Update dma perf test document with below support features:
1. Memory-to-device and device-to-memory copy.
2. Skip support.
3. Scatter-gather support.

Signed-off-by: Amit Prakash Shukla <amitprakashs@marvell.com>
---
 doc/guides/tools/dmaperf.rst | 89 ++++++++++++++++++++++++++----------
 1 file changed, 64 insertions(+), 25 deletions(-)

diff --git a/doc/guides/tools/dmaperf.rst b/doc/guides/tools/dmaperf.rst
index 9e3e78a6b7..4a5702a628 100644
--- a/doc/guides/tools/dmaperf.rst
+++ b/doc/guides/tools/dmaperf.rst
@@ -5,27 +5,23 @@ dpdk-test-dma-perf Application
 ==============================
 
 The ``dpdk-test-dma-perf`` tool is a Data Plane Development Kit (DPDK) application
-that enables testing the performance of DMA (Direct Memory Access) devices available within DPDK.
-It provides a test framework to assess the performance of CPU and DMA devices
-under various scenarios, such as varying buffer lengths.
-Doing so provides insight into the potential performance
-when using these DMA devices for acceleration in DPDK applications.
+that evaluates the performance of DMA (Direct Memory Access) devices accessible in DPDK environment.
+It provides a benchmark framework to assess the performance of CPU and DMA devices
+under various combinations, such as varying buffer lengths, scatter-gather copy, copying in remote
+memory etc. It helps in evaluating performance of DMA device as hardware acceleration vehicle in
+DPDK application.
 
-It supports memory copy performance tests for now,
-comparing the performance of CPU and DMA automatically in various conditions
-with the help of a pre-set configuration file.
+In addition, this tool supports memory-to-memory, memory-to-device and device-to-memory copy tests,
+to compare the performance of CPU and DMA capabilities under various conditions with the help of a
+pre-set configuration file.
 
 
 Configuration
 -------------
 
-This application uses inherent DPDK EAL command-line options
-as well as custom command-line options in the application.
-An example configuration file for the application is provided
-and gives the meanings for each parameter.
-
-Here is an extracted sample from the configuration file
-(the complete sample can be found in the application source directory):
+Along with EAL command-line arguments, this application supports various parameters for the
+benchmarking through a configuration file. An example configuration file is provided below along
+with the application to demonstrate all the parameters.
 
 .. code-block:: ini
 
@@ -53,14 +49,35 @@ Here is an extracted sample from the configuration file
    lcore = 3, 4
    eal_args=--in-memory --no-pci
 
+   [case3]
+   skip=1
+   type=DMA_MEM_COPY
+   direction=mem2dev
+   vchan_dev=raddr=0x200000000,coreid=1,pfid=2,vfid=3
+   dma_src_sge=4
+   dma_dst_sge=1
+   mem_size=10
+   buf_size=64,8192,2,MUL
+   dma_ring_size=1024
+   kick_batch=32
+   src_numa_node=0
+   dst_numa_node=0
+   cache_flush=0
+   test_seconds=2
+   lcore_dma=lcore10@0000:00:04.2, lcore11@0000:00:04.3
+   eal_args=--in-memory --file-prefix=test
+
 The configuration file is divided into multiple sections, each section represents a test case.
-The four variables ``mem_size``, ``buf_size``, ``dma_ring_size``, and ``kick_batch``
-can vary in each test case.
-The format for this is ``variable=first,last,increment,ADD|MUL``.
-This means that the first value of the variable is 'first',
-the last value is 'last',
-'increment' is the step size,
-and 'ADD|MUL' indicates whether the change is by addition or multiplication.
+The four mandatory variables ``mem_size``, ``buf_size``, ``dma_ring_size``, and ``kick_batch``
+can vary in each test case. The format for this is ``variable=first,last,increment,ADD|MUL``.
+This means that the first value of the variable is 'first', the last value is 'last',
+'increment' is the step size, and 'ADD|MUL' indicates whether the change is by addition or
+multiplication.
+
+The variables for mem2dev and dev2mem copy are ``direction``, ``vchan_dev`` and can vary in each
+test case. If the direction is not configured, the default is mem2mem copy.
+
+For scatter-gather copy test ``dma_src_sge``, ``dma_dst_sge`` must be configured.
 
 Each case can only have one variable change,
 and each change will generate a scenario, so each case can have multiple scenarios.
@@ -69,10 +86,32 @@ and each change will generate a scenario, so each case can have multiple scenari
 Configuration Parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
+``skip``
+  To skip a test-case, must be configured as ``1``
+
 ``type``
   The type of the test.
   Currently supported types are ``DMA_MEM_COPY`` and ``CPU_MEM_COPY``.
 
+``direction``
+  The direction of data transfer.
+  Currently supported directions:
+
+    * ``mem2mem`` - memory to memory copy
+
+    * ``mem2dev`` - memory to device copy
+
+    * ``dev2mem`` - device to memory copy
+
+``vchan_dev``
+  Comma separated bus related parameters for ``mem2dev`` and ``dev2mem`` copy.
+
+``dma_src_sge``
+  Number of source segments for scatter-gather.
+
+``dma_dst_sge``
+  Number of destination segments for scatter-gather.
+
 ``mem_size``
   The size of the memory footprint.
 
@@ -131,6 +170,6 @@ with the same name as the configuration file with the addition of ``_result.csv`
 Limitations
 -----------
 
-Currently, this tool only supports memory copy performance tests.
-Additional enhancements are possible in the future
-to support more types of tests for DMA devices and CPUs.
+DMA copy to/from remote memory address has following limitations:
+
+ * ``vchan_dev`` config will be same for all the configured DMA devices.
-- 
2.34.1