From mboxrd@z Thu Jan 1 00:00:00 1970 From: achiad shochat Subject: Re: [PATCH net-next 05/12] net/mlx5e: Poll rx cq before tx cq to improve round-trip latency Date: Mon, 22 Jun 2015 00:35:37 +0300 Message-ID: References: <1434554789-13758-1-git-send-email-ogerlitz@mellanox.com> <1434554789-13758-6-git-send-email-ogerlitz@mellanox.com> <20150621.102144.267706734504980452.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: ogerlitz@mellanox.com, netdev@vger.kernel.org, amirv@mellanox.com, talal@mellanox.com, saeedm@mellanox.com To: David Miller Return-path: Received: from mail-oi0-f54.google.com ([209.85.218.54]:36586 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753209AbbFUVfi (ORCPT ); Sun, 21 Jun 2015 17:35:38 -0400 Received: by oigb199 with SMTP id b199so68594574oig.3 for ; Sun, 21 Jun 2015 14:35:37 -0700 (PDT) In-Reply-To: <20150621.102144.267706734504980452.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: Hello Dave, In mlx5 the RX processing is broken down into two stages: 1) Hand to kernel SKBs of completed RX packets - @mlx5e_poll_rx_cq() 2) Allocate and post to HW new RX buffers - @mlx5e_post_rx_wqes() Would handling of TX completions in between stages (1) and (2) be OK? On 21 June 2015 at 20:21, David Miller wrote: > From: Or Gerlitz > Date: Wed, 17 Jun 2015 18:26:22 +0300 > >> From: Achiad Shochat >> >> For better round trip latency, handle rx completions before >> tx completions. >> >> Signed-off-by: Achiad Shochat >> Signed-off-by: Saeed Mahameed >> Signed-off-by: Or Gerlitz > > I completely disagree with this change. > > TX completions should always be handled first because they free up resources > and therefore increase the likelyhood that RX processing will not fail due > to lack of resources (memory, etc.). > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in