Re: [dpdk-dev] [PATCH] app/testpmd: fix the default RSS key configuration

[Phil Yang <Phil.Yang@arm.com>]

> -----Original Message-----
> From: oulijun <oulijun@huawei.com>
> Sent: Tuesday, August 4, 2020 9:29 AM
> To: Phil Yang <Phil.Yang@arm.com>; wenzhuo.lu@intel.com;
> beilei.xing@intel.com; bernard.iremonger@intel.com;
> adrien.mazarguil@6wind.com; ferruh.yigit@intel.com
> Cc: dev@dpdk.org; linuxarm@huawei.com; nd <nd@arm.com>
> Subject: Re: [dpdk-dev] [PATCH] app/testpmd: fix the default RSS key
> configuration
> 
> 
> 
> 在 2020/7/17 15:29, Phil Yang 写道:
> > <snip>
> >
> >>>> Subject: [dpdk-dev] [PATCH] app/testpmd: fix the default RSS key
> >>>> configuration
> >>>>
> >>>> When an user runs a flow create cmd to configure an RSS rule
> >>>> without specifying the empty rss actions in testpmd, this mean
> >>>> that the flow gets the default RSS functions. However, the
> >>>> testpmd is not set the default RSS key incorrectly when RSS key
> >>>> is specified in flow create cmd.
> >>> Hi Lijun,
> >>>
> >>> I think it works.
> >>> When we create an RSS flow rule which doesn't specify any 'rss-hash-
> key',
> >> the 'rss-hash-key' will be updated with the default key.
> >>> Step 1:
> >>> testpmd> show port 0 rss-hash key
> >>> RSS functions:
> >>>    all ipv4-frag ipv4-other ipv6-frag ipv6-other ip
> >>> RSS key:
> >>>
> >>
> 4439796BB54C5023B675EA5B124F9F30B8A2C03DDFDC4D02A08C9B334AF64A4
> >> C05C6FA343958D8557D99583AE138C92E81150366
> >>> Step 2:
> >>> testpmd> flow create 0 ingress pattern eth / ipv4 / udp / end actions rss
> >> types ipv4-udp end queues end / end
> >>> Flow rule #0 created
> >>>
> >>> Step 3:
> >>> testpmd> show port 0 rss-hash key
> >>> RSS functions:
> >>>    all ipv4-udp udp
> >>> RSS key:
> >>>
> >>
> 74657374706D6427732064656661756C74205253532068617368206B65792C206F
> >> 7665727269646520697420666F722062657474
> >>>
> >>> Thanks,
> >>> Phil
> >> Yes, However, it is not the default value that users use when testpmd
> >> starts. This may mislead users. When the driver is initialized, the
> >> default key used by the driver is provided for users. The key varies
> >> according to the DPDK vendor.However, after the DPDK is initialized, if
> >> the user runs the flow create command without specifying the rss key,
> >> the driver obtains another default key value, which may be different
> >> from the default value expected by the user.
> > It needs a dummy key.
> > a4391f8bae85 - app/testpmd: set default RSS key as null
> Hi, Phil Yang
>     Yes, I've reviewed the patch("a4391f8bae85 - app/testpmd: set
> default RSS key as null") and read all other people's comments.
> However, the patch has been reverted in V2 and restored to the orginal
> states.  The link as follows:
> https://patches.dpdk.org/patch/47961/

I got your point now.
Your patch makes testpmd using the valid NIC default RSS hash key as the flow rule default RSS, is that right?

The patch looks good to me. Please fix the typo in your commit message and make it more accurate.
For example, you can put the cmd line and the expected output in the commit message. 

> I also don't think the key_len parameter is very profitable
> for users to configure.  Others say that other optimizations will be
> considered later. Do you have any plans?

I have no plans for it now.

Thanks,
Phil