[PATCH v6 3/3] doc: update cryptodev scheduler PMD documentation

[Fan Zhang <roy.fan.zhang@intel.com>]

This patch updates packet size based scheduling mode description.

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
---
 doc/guides/cryptodevs/scheduler.rst    | 15 +++++++++++++++
 doc/guides/rel_notes/release_17_05.rst |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/doc/guides/cryptodevs/scheduler.rst b/doc/guides/cryptodevs/scheduler.rst
index 70fb62e..af54daf 100644
--- a/doc/guides/cryptodevs/scheduler.rst
+++ b/doc/guides/cryptodevs/scheduler.rst
@@ -126,3 +126,18 @@ operation:
    among its slaves in a round-robin manner. This mode may help to fill
    the throughput gap between the physical core and the existing cryptodevs
    to increase the overall performance.
+
+*   **CDEV_SCHED_MODE_PKT_SIZE_DISTR:**
+
+   Packet-size based distribution mode, which works with 2 slaves, the primary
+   slave and the secondary slave, and distributes the enqueued crypto
+   operations to them based on their data lengths. A crypto operation will be
+   distributed to the primary slave if its data length is equal to or bigger
+   than the designated threshold, otherwise it will be handled by the secondary
+   slave.
+
+   A typical usecase in this mode is with the QAT cryptodev as the primary and
+   a software cryptodev as the secondary slave. This may help applications to
+   process additional crypto workload than what the QAT cryptodev can handle on
+   its own, by making use of the available CPU cycles to deal with smaller
+   crypto workloads.
diff --git a/doc/guides/rel_notes/release_17_05.rst b/doc/guides/rel_notes/release_17_05.rst
index 2eecdec..ca44df3 100644
--- a/doc/guides/rel_notes/release_17_05.rst
+++ b/doc/guides/rel_notes/release_17_05.rst
@@ -55,6 +55,11 @@ New Features
 
   sPAPR IOMMU based pci probing enabled for vfio-pci devices.
 
+* **Added packet-size based distribution mode to Cryptodev Scheduler PMD.**
+
+  Packet-size based distribution mode is a scheduling mode that works with
+  2 slaves and distributes the enqueued crypto operations to them based on
+  their data lengths.
 
 Resolved Issues
 ---------------
-- 
2.7.4