From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17CDEECE599 for ; Wed, 16 Oct 2019 23:55:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7655206A4 for ; Wed, 16 Oct 2019 23:55:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="IZ665a5h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394971AbfJPXzm (ORCPT ); Wed, 16 Oct 2019 19:55:42 -0400 Received: from mail-lj1-f196.google.com ([209.85.208.196]:41195 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729939AbfJPXzl (ORCPT ); Wed, 16 Oct 2019 19:55:41 -0400 Received: by mail-lj1-f196.google.com with SMTP id f5so521726ljg.8 for ; Wed, 16 Oct 2019 16:55:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :organization:mime-version:content-transfer-encoding; bh=uL6fp3k8sxcba+4hRLg6z3bVGUawFpouMPeEo11F1YA=; b=IZ665a5hkySLq/BiSDP56h7d2yw2MUJiNDcQBuLZkg8aDlEJu8wi4nh8TgDDKpUs98 PbebXpIjWjcTMg0OdmVGkBhC1iQQfEEW6tQ5xh7qNnNUbzPhD4U+pYVyCnfgAlqnVboV 4fA9d5U3XncRQPKEkBFkKhIjU/yKUgK4C2L7evqRKvhxTGA9zeDHA+R3IP3l/BMrGrX9 6HPzIZaMvXxKp7RzmM3L+RzAfAdxG9f0dnWLqj5b64x+Omqds5LEAw2cFpvJbJ65ijYN b1UVfoFQr5aTaNffNqFs4VYnf5sb29O1qUFWG22wrKUknxFb17+lffMsG4eJjw72+Yck uoAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:organization:mime-version:content-transfer-encoding; bh=uL6fp3k8sxcba+4hRLg6z3bVGUawFpouMPeEo11F1YA=; b=s1XETu+ql7YPkd6O9qR1bn4Izb3Yj79zGvyuFyWljlDKH9TY//DCpXsk5WwWvOFFB0 pjUs7xQlZmDFfm7IptBgr4z7oRq16+2LqxA5yJn4uAUwfMDIAkvORX3FIKZJ7IqK97uv ETIuvzV6r4y3jy26pB1O+A2n8vizrdBVFhf3soOw6gTljX35JWP5DLW0G0Knv1wY4L17 81/UBgy6xSbbKtBmWqGBHZzTDA+umpzQbIZZYg+leOjWLfXZ1NpPfDrkcGNQeTWY61IM zzD56ESjv+t5L6XIdlWbfxg1GDcaYmUowUxSsFdgWbS0lUKy5F6VJ+texPA/1FLwBRFn OB8g== X-Gm-Message-State: APjAAAU6nFDV4RwN8w/zUIbP7qR6BN9eGmzXqnDGPfCuUaqV1WfCYE4R +APyePD7nlVK0WHG3qXcxVS1rw== X-Google-Smtp-Source: APXvYqwGhBRjmKVYlwbCP/vEt1QxfqKD7/45X968rLo5ogY8/GIT9GWGoCfAMCepuOQdA/89tEfnkQ== X-Received: by 2002:a2e:a179:: with SMTP id u25mr444028ljl.33.1571270139670; Wed, 16 Oct 2019 16:55:39 -0700 (PDT) Received: from cakuba.netronome.com ([66.60.152.14]) by smtp.gmail.com with ESMTPSA id h3sm127788lfc.26.2019.10.16.16.55.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2019 16:55:39 -0700 (PDT) Date: Wed, 16 Oct 2019 16:55:31 -0700 From: Jakub Kicinski To: Jeff Kirsher Cc: davem@davemloft.net, Robert Beckett , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, Aaron Brown Subject: Re: [net-next 2/7] igb: add rx drop enable attribute Message-ID: <20191016165531.26854b0e@cakuba.netronome.com> In-Reply-To: <20191016234711.21823-3-jeffrey.t.kirsher@intel.com> References: <20191016234711.21823-1-jeffrey.t.kirsher@intel.com> <20191016234711.21823-3-jeffrey.t.kirsher@intel.com> Organization: Netronome Systems, Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 16 Oct 2019 16:47:06 -0700, Jeff Kirsher wrote: > From: Robert Beckett > > To allow userland to enable or disable dropping packets when descriptor > ring is exhausted, add RX_DROP_EN private flag. > > This can be used in conjunction with flow control to mitigate packet storms > (e.g. due to network loop or DoS) by forcing the network adapter to send > pause frames whenever the ring is close to exhaustion. > > By default this will maintain previous behaviour of enabling dropping of > packets during ring buffer exhaustion. > Some use cases prefer to not drop packets upon exhaustion, but instead > use flow control to limit ingress rates and ensure no dropped packets. > This is useful when the host CPU cannot keep up with packet delivery, > but data delivery is more important than throughput via multiple queues. > > Userland can set this flag to 0 via ethtool to disable packet dropping. > > Signed-off-by: Robert Beckett > Tested-by: Aaron Brown > Signed-off-by: Jeff Kirsher How is this different than enabling/disabling flow control.. ethtool -a/-A