[PATCH v4] net/ice: improve performance of RX timestamp offload

[Zhang, Qi Z]

> -----Original Message-----
> From: Kevin Traynor <ktraynor at redhat.com>
> Sent: Thursday, March 24, 2022 7:17 PM
> To: Zhang, Qi Z <qi.z.zhang at intel.com>; Wu, Wenjun1
> <wenjun1.wu at intel.com>; dev at dpdk.org; Yang, Qiming
> <qiming.yang at intel.com>
> Cc: Van Haaren, Harry <harry.van.haaren at intel.com>; Su, Simei
> <simei.su at intel.com>; Luca Boccassi <bluca at debian.org>; Christian Ehrhardt
> <christian.ehrhardt at canonical.com>
> Subject: Re: [PATCH v4] net/ice: improve performance of RX timestamp
> offload
> 
> On 24/03/2022 09:09, Zhang, Qi Z wrote:
> >
> >
> >> -----Original Message-----
> >> From: Wu, Wenjun1 <wenjun1.wu at intel.com>
> >> Sent: Monday, February 28, 2022 3:36 PM
> >> To: dev at dpdk.org; Zhang, Qi Z <qi.z.zhang at intel.com>; Yang, Qiming
> >> <qiming.yang at intel.com>
> >> Cc: Van Haaren, Harry <harry.van.haaren at intel.com>; Su, Simei
> >> <simei.su at intel.com>; Wu, Wenjun1 <wenjun1.wu at intel.com>
> >> Subject: [PATCH v4] net/ice: improve performance of RX timestamp
> >> offload
> >>
> >> Previously, each time a burst of packets is received, SW reads HW
> >> register and assembles it and the timestamp from descriptor together
> >> to get the complete 64 bits timestamp.
> >>
> >> This patch optimizes the algorithm. The SW only needs to check the
> >> monotonicity of the low 32bits timestamp to avoid crossing borders.
> >> Each time before SW receives a burst of packets, it should check the
> >> time difference between current time and last update time to avoid
> >> the low 32 bits timestamp cycling twice.
> >>
> >> Signed-off-by: Wenjun Wu <wenjun1.wu at intel.com>
> >
> > Added cc stable
> >
> 
> Hi Qi. The DPDK documentation has guidance about what should be
> backported to LTS [0] and distinguishes between fixes and performance
> improvements. Please try and stick with this when applying patches or let LTS
> maintainers know if there is a debatable case.

Thanks for the comments
Yes, actually this is about a 50% ~ 70% performance improvement, which maybe critical for some performance sensitive use cases.(e.g. network forensics)
So I'd like to defend with below case

An existing feature in LTS is not usable as intended without it.

Thanks
Qi

> 
> thanks,
> Kevin.
> 
> [0]
> http://doc.dpdk.org/guides-21.11/contributing/stable.html#what-changes-
> should-be-backported

> 
> > Acked-by: Qi Zhang <qi.z.zhang at intel.com>
> >
> > Applied to dpdk-next-net-intel.
> >
> > Thanks
> > Qi
> >
>