From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Hanoch Haim (hhaim)" Subject: net/i40e: latency issue due fix interrupt throttling setting in PF Date: Mon, 20 Nov 2017 15:18:50 +0000 Message-ID: <3f57eb6982af4bb9aae69bce67233d89@XCH-RTP-017.cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "Wu, Jingjing (jingjing.wu@intel.com)" , "Hanoch Haim (hhaim)" To: "dev@dpdk.org" Return-path: Received: from alln-iport-2.cisco.com (alln-iport-2.cisco.com [173.37.142.89]) by dpdk.org (Postfix) with ESMTP id 699C47CC2 for ; Mon, 20 Nov 2017 16:18:52 +0100 (CET) Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi All, While integrating dpdk17.11 into TRex latest code a new latency issue is ob= served (i40e is very sensitive because it has very good resolution due to = Qos configuration). git bitsec found the following commit. With this commit we observe high spikes of Rx latency (~40usec) vs (~8usec)= . Any idea why? I can send how to reproduce this, it is very simple. cfd662d22e7bddb4ba41dbd1384f8497f38c2b4e is the first bad commit commit cfd662d22e7bddb4ba41dbd1384f8497f38c2b4e Author: Jingjing Wu > Date: Thu Aug 24 09:57:51 2017 +0800 net/i40e: fix interrupt throttling setting in PF As no matter the PF host driver is DPDK or other kernel drivers, they are sharing the same virtchnnl interfaces to communicate to VFs. To follow the generic interface, DPDK PF need to set Interrupt Throttling (ITR) index according to the rxitr_idx from virtchnnl instead of ITR_NONE. Fixes: 6d59e4ea74a6 ("net/i40e: change version number to support Linux = VF") Cc: stable@dpdk.org Signed-off-by: Jingjing Wu > Thanks, Hanoh