[dpdk-stable] patch 'doc: fix default burst size in testpmd' has been queued to stable release 19.11.10

[christian.ehrhardt at canonical.com]

Hi,

FYI, your patch has been queued to stable release 19.11.10

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/12/21. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/cpaelzer/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/cpaelzer/dpdk-stable-queue/commit/848d502d037115255a7737a96343615c38b67f46

Thanks.

Christian Ehrhardt <christian.ehrhardt at canonical.com>

---
>From 848d502d037115255a7737a96343615c38b67f46 Mon Sep 17 00:00:00 2001
From: Ajit Khaparde <ajit.khaparde at broadcom.com>
Date: Fri, 28 May 2021 10:45:29 -0700
Subject: [PATCH] doc: fix default burst size in testpmd

[ upstream commit 478614ee1f62e172c4d4770f157fc9bbb6563523 ]

Default burst size in testpmd has been changed from 16 to 32
for some time now. But the documentation had not been updated.

Fixes: 836853d3d4cf7 ("app/testpmd: increase default burst size to 32")

Signed-off-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
---
 doc/guides/prog_guide/writing_efficient_code.rst | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/doc/guides/prog_guide/writing_efficient_code.rst b/doc/guides/prog_guide/writing_efficient_code.rst
index 849f63efe7..88e6bde047 100644
--- a/doc/guides/prog_guide/writing_efficient_code.rst
+++ b/doc/guides/prog_guide/writing_efficient_code.rst
@@ -143,20 +143,21 @@ In order to achieve higher throughput,
 the DPDK attempts to aggregate the cost of processing each packet individually by processing packets in bursts.
 
 Using the testpmd application as an example,
-the burst size can be set on the command line to a value of 16 (also the default value).
-This allows the application to request 16 packets at a time from the PMD.
+the burst size can be set on the command line to a value of 32 (also the default value).
+This allows the application to request 32 packets at a time from the PMD.
 The testpmd application then immediately attempts to transmit all the packets that were received,
-in this case, all 16 packets.
+in this case, all 32 packets.
 
 The packets are not transmitted until the tail pointer is updated on the corresponding TX queue of the network port.
 This behavior is desirable when tuning for high throughput because
-the cost of tail pointer updates to both the RX and TX queues can be spread across 16 packets,
+the cost of tail pointer updates to both the RX and TX queues can be spread
+across 32 packets,
 effectively hiding the relatively slow MMIO cost of writing to the PCIe* device.
 However, this is not very desirable when tuning for low latency because
-the first packet that was received must also wait for another 15 packets to be received.
-It cannot be transmitted until the other 15 packets have also been processed because
+the first packet that was received must also wait for another 31 packets to be received.
+It cannot be transmitted until the other 31 packets have also been processed because
 the NIC will not know to transmit the packets until the TX tail pointer has been updated,
-which is not done until all 16 packets have been processed for transmission.
+which is not done until all 32 packets have been processed for transmission.
 
 To consistently achieve low latency, even under heavy system load,
 the application developer should avoid processing packets in bunches.
-- 
2.32.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-08-10 15:11:13.550661632 +0200
+++ 0012-doc-fix-default-burst-size-in-testpmd.patch	2021-08-10 15:11:12.914637350 +0200
@@ -1 +1 @@
-From 478614ee1f62e172c4d4770f157fc9bbb6563523 Mon Sep 17 00:00:00 2001
+From 848d502d037115255a7737a96343615c38b67f46 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 478614ee1f62e172c4d4770f157fc9bbb6563523 ]
+
@@ -10 +11,0 @@
-Cc: stable at dpdk.org
@@ -18 +19 @@
-index 7baeaae431..a61e8320ae 100644
+index 849f63efe7..88e6bde047 100644