Re: [dpdk-dev] [PATCH v7] net/i40e: add interface to use latest vec path

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Yigit, Ferruh
> Sent: Tuesday, September 18, 2018 9:01 PM
> To: Li, Xiaoyun <xiaoyun.li@intel.com>; Xing, Beilei <beilei.xing@intel.com>;
> Zhang, Qi Z <qi.z.zhang@intel.com>
> Cc: dev@dpdk.org; Yang, Zhiyong <zhiyong.yang@intel.com>;
> thomas@monjalon.net; Richardson, Bruce <bruce.richardson@intel.com>
> Subject: Re: [PATCH v7] net/i40e: add interface to use latest vec path
> 
> On 9/18/2018 3:22 AM, Xiaoyun Li wrote:
> > For IA, the AVX2 vector path is only recommended to be used on later
> > platforms (identified by AVX512 support, like SKL etc.) This is
> > because performance benchmark shows downgrade when running AVX2
> vector
> > path on early platform (BDW/HSW) in some cases. But we still observe
> > perf gain with some real work loading.
> >
> > So this patch introduced the new devarg use-latest-supported-vec to
> > force the driver always selecting the latest supported vec path. Then
> > apps are able to take AVX2 path on early platforms. And this logic can
> > be re-used if we will have AVX512 vec path in future.
> >
> > This patch only affects IA platforms. The selected vec path would be
> > like the following:
> >   Without devarg/devarg = 0:
> >   Machine	vPMD
> >   AVX512F	AVX2
> >   AVX2	SSE4.2
> >   SSE4.2	SSE4.2
> >   <SSE4.2	Not Supported
> >
> >   With devarg = 1
> >   Machine	vPMD
> >   AVX512F	AVX2
> >   AVX2	AVX2
> >   SSE4.2	SSE4.2
> >   <SSE4.2	Not Supported
> >
> > Other platforms can also apply the same logic if necessary in future.
> >
> > Signed-off-by: Xiaoyun Li <xiaoyun.li@intel.com>
> > ---
> > v7:
> >  * Use uint_8 instead of bool type for struct member.
> > v6:
> >  * Polish the doc and commit log.
> >  * Use rte_kvargs_process instead of directly kvlist internals.
> > v5:
> >  * Simpify the rx set function.
> > v4:
> >  * Polish the codes.
> > v3:
> >  * Polish the doc and commit log.
> > v2:
> >  * Correct the calling of the wrong function last time.
> >  * Fix seg fault bug.
> > ---
> >  doc/guides/nics/i40e.rst               |   8 ++
> 
> Doc is causing warning:
> doc/guides/nics/i40e.rst:172: WARNING: Unexpected indentation.
> 
> Except from that,
> Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi