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Thu, 24 Mar 2022 05:17:46 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxVtiaP2O5BH7i9HtmOQbIXS6LcXmIze4eghtxR1FtZgSJj/WuIJW4KsgUETLKFQo2iT1DETA== X-Received: by 2002:a5d:4688:0:b0:203:f0cc:da10 with SMTP id u8-20020a5d4688000000b00203f0ccda10mr4457308wrq.87.1648124266399; Thu, 24 Mar 2022 05:17:46 -0700 (PDT) Received: from [192.168.0.36] ([78.17.178.139]) by smtp.gmail.com with ESMTPSA id m20-20020a05600c4f5400b0038b5162260csm2826547wmq.23.2022.03.24.05.17.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Mar 2022 05:17:45 -0700 (PDT) Message-ID: Date: Thu, 24 Mar 2022 12:17:44 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 To: "Zhang, Qi Z" , "Wu, Wenjun1" , "dev@dpdk.org" , "Yang, Qiming" Cc: "Van Haaren, Harry" , "Su, Simei" , Luca Boccassi , Christian Ehrhardt References: <20220222062612.335622-1-wenjun1.wu@intel.com> <20220228073607.2249410-1-wenjun1.wu@intel.com> <3da8efff430e43808657c353c748ea9d@intel.com> <4d81601b-6aa5-3746-a888-7a290e071997@redhat.com> <87ea19805e604ca5b85366cf11028a09@intel.com> From: Kevin Traynor Subject: Re: [PATCH v4] net/ice: improve performance of RX timestamp offload In-Reply-To: <87ea19805e604ca5b85366cf11028a09@intel.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ktraynor@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 24/03/2022 11:51, Zhang, Qi Z wrote: > > >> -----Original Message----- >> From: Kevin Traynor >> Sent: Thursday, March 24, 2022 7:17 PM >> To: Zhang, Qi Z ; Wu, Wenjun1 >> ; dev@dpdk.org; Yang, Qiming >> >> Cc: Van Haaren, Harry ; Su, Simei >> ; Luca Boccassi ; Christian Ehrhardt >> >> 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 >>>> Sent: Monday, February 28, 2022 3:36 PM >>>> To: dev@dpdk.org; Zhang, Qi Z ; Yang, Qiming >>>> >>>> Cc: Van Haaren, Harry ; Su, Simei >>>> ; Wu, Wenjun1 >>>> 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 >>> >>> 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. > Thanks > Qi > >> >> thanks, >> Kevin. >> >> [0] >> http://doc.dpdk.org/guides-21.11/contributing/stable.html#what-changes- >> should-be-backported > >> >>> Acked-by: Qi Zhang >>> >>> Applied to dpdk-next-net-intel. >>> >>> Thanks >>> Qi >>> >> >