> -----Original Message----- > From: Kevin Traynor <ktray...@redhat.com> > Sent: Thursday, March 24, 2022 9:45 PM > To: Zhang, Qi Z <qi.z.zh...@intel.com>; Wu, Wenjun1 > <wenjun1...@intel.com>; dev@dpdk.org; Yang, Qiming > <qiming.y...@intel.com> > Cc: Van Haaren, Harry <harry.van.haa...@intel.com>; Su, Simei > <simei...@intel.com>; Luca Boccassi <bl...@debian.org>; Christian Ehrhardt > <christian.ehrha...@canonical.com> > Subject: Re: [PATCH v4] net/ice: improve performance of RX timestamp > offload > > On 24/03/2022 13:05, Zhang, Qi Z wrote: > > > > > >> -----Original Message----- > >> From: Kevin Traynor <ktray...@redhat.com> > >> Sent: Thursday, March 24, 2022 8:18 PM > >> To: Zhang, Qi Z <qi.z.zh...@intel.com>; Wu, Wenjun1 > >> <wenjun1...@intel.com>; dev@dpdk.org; Yang, Qiming > >> <qiming.y...@intel.com> > >> Cc: Van Haaren, Harry <harry.van.haa...@intel.com>; Su, Simei > >> <simei...@intel.com>; Luca Boccassi <bl...@debian.org>; Christian > >> Ehrhardt <christian.ehrha...@canonical.com> > >> Subject: Re: [PATCH v4] net/ice: improve performance of RX timestamp > >> offload > >> > >> On 24/03/2022 11:51, Zhang, Qi Z wrote: > >>> > >>> > >>>> -----Original Message----- > >>>> From: Kevin Traynor <ktray...@redhat.com> > >>>> Sent: Thursday, March 24, 2022 7:17 PM > >>>> To: Zhang, Qi Z <qi.z.zh...@intel.com>; Wu, Wenjun1 > >>>> <wenjun1...@intel.com>; dev@dpdk.org; Yang, Qiming > >>>> <qiming.y...@intel.com> > >>>> Cc: Van Haaren, Harry <harry.van.haa...@intel.com>; Su, Simei > >>>> <simei...@intel.com>; Luca Boccassi <bl...@debian.org>; Christian > >>>> Ehrhardt <christian.ehrha...@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...@intel.com> > >>>>>> Sent: Monday, February 28, 2022 3:36 PM > >>>>>> To: dev@dpdk.org; Zhang, Qi Z <qi.z.zh...@intel.com>; Yang, > >>>>>> Qiming <qiming.y...@intel.com> > >>>>>> Cc: Van Haaren, Harry <harry.van.haa...@intel.com>; Su, Simei > >>>>>> <simei...@intel.com>; Wu, Wenjun1 <wenjun1...@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...@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. > >>> > >> > >> If that is the case, then I think the commitlog should be re-written. > >> It just talks about the code changes, there's nothing about an impact > >> to an existing use case that was unusuable and is now fixed. > > > > OK, I updated with below commit log in dpdk-next-net-intel. > > Kevin , Wenjun, let me know if anything I missed. > > > > 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. > > > > The patch proved a 50% ~ 70% single core performance improvement on > a > > main stream Xeon server, and it is necessary to be backport to LTS > release, > > as this fix the performance gap for some use cases. > > > > The comment about backport to LTS can be removed. That is an operational > comment, so not really relevant to a future reader trying to understand the > commit.
Yes, removed the unnecessary comment. The patch proved a 50% ~ 70% single core performance improvement on a main stream Xeon server, this fix the performance gap for some use cases. > > thanks, > Kevin. > > > Thanks > > Qi > > > >> > >>> Thanks > >>> Qi > >>> > >>>> > >>>> thanks, > >>>> Kevin. > >>>> > >>>> [0] > >>>> http://doc.dpdk.org/guides-21.11/contributing/stable.html#what-chan > >>>> ge > >>>> s- > >>>> should-be-backported > >>> > >>>> > >>>>> Acked-by: Qi Zhang <qi.z.zh...@intel.com> > >>>>> > >>>>> Applied to dpdk-next-net-intel. > >>>>> > >>>>> Thanks > >>>>> Qi > >>>>> > >>>> > >>> > >
