From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olivier MATZ Subject: Re: [PATCH v2 03/20] i40e: call i40e_txd_enable_checksum only for offloaded packets Date: Tue, 10 Feb 2015 18:06:56 +0100 Message-ID: <54DA3AB0.3040500@6wind.com> References: <1422623775-8050-1-git-send-email-olivier.matz@6wind.com> <1423041925-26956-1-git-send-email-olivier.matz@6wind.com> <1423041925-26956-4-git-send-email-olivier.matz@6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: "Zhang, Helin" , "dev-VfR2kkLFssw@public.gmane.org" Return-path: In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" Hi Helin, On 02/10/2015 07:03 AM, Zhang, Helin wrote: >> /* Enable checksum offloading */ >> cd_tunneling_params = 0; >> - i40e_txd_enable_checksum(ol_flags, &td_cmd, &td_offset, >> - l2_len, l3_len, outer_l2_len, >> - outer_l3_len, >> - &cd_tunneling_params); >> + if (ol_flags & I40E_TX_CKSUM_OFFLOAD_MASK) { > likely should be added. I would say unlikely() instead. I think the non-offload case should be the default one. What do you think? >> + i40e_txd_enable_checksum(ol_flags, &td_cmd, &td_offset, >> + l2_len, l3_len, outer_l2_len, >> + outer_l3_len, >> + &cd_tunneling_params); >> + } > As this code changes are in fast path, performance regression test is needed. I would > like to see the performance difference with or without this patch set. Hopefully nothing > different. If you need any helps, just let me know. I'm sorry, I won't have the needed resources to bench this as I would have to setup a performance platform with i40e devices. But I'm pretty sure that the code in non-offload case would be faster with this patch as it will avoid many operations in i40e_txd_enable_checksum(). For the offload case, as we also removed the if (l2_len == 0) and if (l3_len == 0), I think there are also less tests than before my patch series. So in my opinion, adding this test does not really justify to check the performance. Regards, Olivier