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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 42A8EC4724C for ; Fri, 1 May 2020 14:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F5BE20857 for ; Fri, 1 May 2020 14:47:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gZ0n49WC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729668AbgEAOrb (ORCPT ); Fri, 1 May 2020 10:47:31 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:22708 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729245AbgEAOr3 (ORCPT ); Fri, 1 May 2020 10:47:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588344448; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TAjswuo/nfZVxK4WmcUPw+t1lhJhZPT7S8oViDh5c/M=; b=gZ0n49WCj0NWj2ULNX6/drg10r9zbl06ExpDL3zTyMK9Nk+HDRGBS1ahMhocTnlEwhF7Fn +/YNt/i3MMyBOkNczjZXlbZiqb9yot/ZDikgSY0R38k81zH9wwQfSmruAFt4Hd/JJLFkL1 Nc9YyPx/aD+FDhf08V7d78ZIwVJw18o= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-323-XycBYBrvMfGAR2SyAfIh3Q-1; Fri, 01 May 2020 10:47:19 -0400 X-MC-Unique: XycBYBrvMfGAR2SyAfIh3Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E4DD1800D4A; Fri, 1 May 2020 14:47:16 +0000 (UTC) Received: from carbon (unknown [10.40.208.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2A2A56A94C; Fri, 1 May 2020 14:47:04 +0000 (UTC) Date: Fri, 1 May 2020 16:47:03 +0200 From: Jesper Dangaard Brouer To: Haiyang Zhang Cc: "sameehj@amazon.com" , Wei Liu , KY Srinivasan , Stephen Hemminger , "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , "zorik@amazon.com" , "akiyano@amazon.com" , "gtzalik@amazon.com" , Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= , Daniel Borkmann , Alexei Starovoitov , John Fastabend , Alexander Duyck , Jeff Kirsher , David Ahern , Willem de Bruijn , Ilias Apalodimas , Lorenzo Bianconi , Saeed Mahameed , "steffen.klassert@secunet.com" , brouer@redhat.com Subject: Re: [PATCH net-next v2 12/33] hv_netvsc: add XDP frame size to driver Message-ID: <20200501164703.75eb5737@carbon> In-Reply-To: References: <158824557985.2172139.4173570969543904434.stgit@firesoul> <158824568241.2172139.9308631605958332864.stgit@firesoul> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 30 Apr 2020 14:20:20 +0000 Haiyang Zhang wrote: > > -----Original Message----- > > From: Jesper Dangaard Brouer > > > > The hyperv NIC drivers XDP implementation is rather disappointing as it will > > be a slowdown to enable XDP on this driver, given it will allocate a new page > > for each packet and copy over the payload, before invoking the XDP BPF- > > prog. > > This needs correction. As I said previously -- > This statement is not accurate -- The data path of netvsc driver does memory > allocation and copy even without XDP, so it's not "a slowdown to enable XDP". Okay, I have changed the paragraph text to: The hyperv NIC driver does memory allocation and copy even without XDP. In XDP mode it will allocate a new page for each packet and copy over the payload, before invoking the XDP BPF-prog. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer