Re: [dpdk-dev] [PATCH] app/testpmd: set default RSS key as null

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 10/21/2020 11:07 AM, Lijun Ou wrote:
> From: Ophir Munk <ophirmu@mellanox.com>
> 
> When creating an RSS rule without specifying a key (see [1]) it is
> expected that the device will use the default key.
> A NULL key is used to indicate to a PMD it should use
> its default key, however testpmd assigns a non-NULL dummy key
> (see [2]) instead.
> This does not enable testing any PMD behavior when the RSS key is not
> specified. This commit fixes this limitation by setting key to NULL.
> Also, it fixes the Scenario [3] that enable default RSS action by
> setting key=NULL and key_len!=0.
> [1]
> RSS rule example without specifying a key:
> flow create 0 ingress <pattern> / end actions rss queues 0 1 end / end
> [2]
> Testpmd default key assignment:
> .key= "testpmd's default RSS hash key, "
> "override it for better balancing"
> [3]
> flow create 0 <pattern> actions rss queues 0 1 end key_len 40 / end
> 
> fixes refer to the link: https://patches.dpdk.org/patch/80898/
> 
> Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> Signed-off-by: Lijun Ou <oulijun@huawei.com>

Applied to dpdk-next-net/main, thanks.


Updated the commit log as below:

Author: Lijun Ou <oulijun@huawei.com>
Date:   Wed Oct 21 18:07:10 2020 +0800

     app/testpmd: fix RSS key for flow API RSS rule

     When a flow API RSS rule is issued in testpmd, device RSS key is changed
     unexpectedly, device RSS key is changed to the testpmd default RSS key.

     Consider the following usage with testpmd:
     1. first, startup testpmd:
      testpmd> show port 0 rss-hash key
      RSS functions: all ipv4-frag ipv4-other ipv6-frag ipv6-other ip
      RSS key: 6D5A56DA255B0EC24167253D43A38FB0D0CA2BCBAE7B30B477CB2DA38030F
               20C6A42B73BBEAC01FA
     2. create a rss rule
      testpmd> flow create 0 ingress pattern eth / ipv4 / udp / end \
               actions rss types ipv4-udp end queues end / end

     3. show rss-hash key
      testpmd> show port 0 rss-hash key
      RSS functions: all ipv4-udp udp
      RSS key: 74657374706D6427732064656661756C74205253532068617368206B65792
               C206F76657272696465

     This is because testpmd always sends a key with the RSS rule,
     if user provides a key as part of the rule that key is used, if user
     doesn't provide a key, testpmd default key is sent to the PMDs, which is
     causing device programmed RSS key to be changed.

     There was a previous attempt to fix the same issue [1], but it has been
     reverted back [2] because of the crash when 'key_len' is provided
     without 'key'.

     This patch follows the same approach with the initial fix [1] but also
     addresses the crash.

     After change, testpmd RSS key is 'NULL' by default, if user provides a
     key as part of rule it is used, if not no key is sent to the PMDs at all

     [1]
     Commit a4391f8bae85 ("app/testpmd: set default RSS key as null")

     [2]
     Commit f3698c3d09a6 ("app/testpmd: revert setting default RSS")

     Fixes: d0ad8648b1c5 ("app/testpmd: fix RSS flow action configuration")
     Cc: stable@dpdk.org

     Signed-off-by: Lijun Ou <oulijun@huawei.com>
     Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
     Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>