doc: add cycle-count mode in compression perf tool

This commit adds release notes and updates documentation for
the cycle-count mode added to the compression performance tool.

Fixes: 2695db95a147 ("test/compress: add cycle-count mode to perf tool")
Signed-off-by: Artur Trybula <arturx.trybula@intel.com>
Acked-by: Adam Dybkowski <adamx.dybkowski@intel.com>

diff --git a/doc/guides/rel_notes/release_20_02.rst b/doc/guides/rel_notes/release_20_02.rst
index c7482c228e2b9229ef301a58dae5578be6e749f6..0c56f0e5cad090e8d9572ff3edfdc5c80198f766 100644 (file)
--- a/doc/guides/rel_notes/release_20_02.rst
+++ b/doc/guides/rel_notes/release_20_02.rst
@@ -195,6 +195,11 @@ New Features
   Add event device support for ``l3fwd`` sample application. It demonstrates
   usage of poll and event mode IO mechanism under a single application.
 
+* **Added cycle-count mode to the compression performance tool.**
+
+  Enhanced the compression performance tool by adding a cycle-count mode
+  which can be used to help measure and tune hardware and software PMDs.
+
 
 Removed Items
 -------------

diff --git a/doc/guides/tools/comp_perf.rst b/doc/guides/tools/comp_perf.rst
index 6c59c8403d704ab01c192390f7657d5b54da108b..ee585d10246efdede600c5bfdf71201d2aa403dd 100644 (file)
--- a/doc/guides/tools/comp_perf.rst
+++ b/doc/guides/tools/comp_perf.rst
@@ -14,8 +14,16 @@ which are passed to compress device with compression operations.
 Then, the output buffers are fed into the decompression stage, and the resulting
 data is compared against the original data (verification phase). After that,
 a number of iterations are performed, compressing first and decompressing later,
-to check the throughput rate
-(showing cycles/iteration, cycles/Byte and Gbps, for compression and decompression).
+to check the throughput rate (showing cycles/iteration, cycles/Byte and Gbps,
+for compression and decompression).
+Another option: ``pmd-cyclecount``, gives the user the opportunity to measure
+the number of cycles per operation for the 3 phases: setup, enqueue_burst and
+dequeue_burst, for both compression and decompression. An optional delay can be
+inserted between enqueue and dequeue so no cycles are wasted in retries while
+waiting for a hardware device to finish. Although artificial, this allows
+to measure the minimum offload cost which could be achieved in a perfectly
+tuned system. Comparing the results of the two tests gives information about
+the trade-off between throughput and cycle-count.
 
 .. Note::
 
@@ -56,7 +64,7 @@ See the DPDK Getting Started Guides for more information on these options.
 Application Options
 ~~~~~~~~~~~~~~~~~~~
 
- ``--ptest [benchmark/verify]``: set test type (default: benchmark)
+ ``--ptest [throughput/verify/pmd-cyclecount]``: set test type (default: throughput)
 
  ``--driver-name NAME``: compress driver to use
 
@@ -84,6 +92,8 @@ Application Options
 
  ``--external-mbufs``: allocate and use memzones as external buffers instead of keeping the data directly in mbuf areas
 
+ ``--cc-delay-us N``: delay between enqueue and dequeue operations in microseconds, valid only for the cyclecount test (default: 500 us)
+
  ``-h``: prints this help