From patchwork Mon Jun 22 13:21:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Magnus Karlsson X-Patchwork-Id: 1314371 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49r96W0RYlz9sDX for ; Mon, 22 Jun 2020 23:21:39 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728919AbgFVNVi (ORCPT ); Mon, 22 Jun 2020 09:21:38 -0400 Received: from mga09.intel.com ([134.134.136.24]:27253 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728100AbgFVNVg (ORCPT ); Mon, 22 Jun 2020 09:21:36 -0400 IronPort-SDR: E+TzF6ptoA31tgIrkcvCPM/e4tagpBPDMUpo/EQ9W/0vLvSoTU7zkoZwu2vyObb9ocySEO45qp gzzjIKLGqtSg== X-IronPort-AV: E=McAfee;i="6000,8403,9659"; a="145265645" X-IronPort-AV: E=Sophos;i="5.75,266,1589266800"; d="scan'208";a="145265645" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2020 06:21:36 -0700 IronPort-SDR: Y6DeN6G1KbLRqCzY2W/zor7KlrobA64xDCrmyRGysBggyOEV8tR2Zl5PARvl2KU5+cpQdpL+EE r7Qp3OduHbfg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,266,1589266800"; d="scan'208";a="422628535" Received: from juergenr-mobl.ger.corp.intel.com (HELO localhost.localdomain) ([10.252.33.83]) by orsmga004.jf.intel.com with ESMTP; 22 Jun 2020 06:21:34 -0700 From: Magnus Karlsson To: magnus.karlsson@intel.com, bjorn.topel@intel.com, intel-wired-lan@lists.osuosl.org, jeffrey.t.kirsher@intel.com Cc: maciej.fijalkowski@intel.com, maciejromanfijalkowski@gmail.com, netdev@vger.kernel.org Subject: [PATCH net-next 2/2] i40e: eliminate division in napi_poll data path Date: Mon, 22 Jun 2020 15:21:23 +0200 Message-Id: <1592832083-23249-3-git-send-email-magnus.karlsson@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1592832083-23249-1-git-send-email-magnus.karlsson@intel.com> References: <1592832083-23249-1-git-send-email-magnus.karlsson@intel.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Eliminate a division in the napi_poll data path. This division is executed even though it is only needed in the rare case when there are not enough interrupt lines so they have to be shared between queue pairs. Instead, just test for this case and only execute the division if needed. The code has been lifted from the ice driver. Signed-off-by: Magnus Karlsson --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 0ce9d1e..da73a7d 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -2595,10 +2595,16 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) if (budget <= 0) goto tx_only; - /* We attempt to distribute budget to each Rx queue fairly, but don't - * allow the budget to go below 1 because that would exit polling early. - */ - budget_per_ring = max(budget/q_vector->num_ringpairs, 1); + /* normally we have 1 Rx ring per q_vector */ + if (unlikely(q_vector->num_ringpairs > 1)) + /* We attempt to distribute budget to each Rx queue fairly, but + * don't allow the budget to go below 1 because that would exit + * polling early. + */ + budget_per_ring = max_t(int, budget / q_vector->num_ringpairs, 1); + else + /* Max of 1 Rx ring in this q_vector so give it the budget */ + budget_per_ring = budget; i40e_for_each_ring(ring, q_vector->rx) { int cleaned = ring->xsk_umem ?