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 538C7C1975A for ; Wed, 25 Mar 2020 16:00:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 18F0220409 for ; Wed, 25 Mar 2020 16:00:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="B2/uL6C6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbgCYQAL (ORCPT ); Wed, 25 Mar 2020 12:00:11 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:54450 "EHLO us-smtp-delivery-74.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727538AbgCYQAL (ORCPT ); Wed, 25 Mar 2020 12:00:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585152010; 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=jx3fIM00QqkeK8qc5H/T95S4XN7fh+fI9pSZ3ndg7X0=; b=B2/uL6C6xcFs9umLEIPc6gDTFKpN8FV4jeUy2YaVIJOnCxnAXEn//j430S+iGG44Fg3r31 2Nozte3RHx5md9xdzVVPOnFGardW5Gdb8cCV5JAECT3ymB9yHl+iFfiZOU3xKi1q4Bf7lT IW76CtB4kVp/w6p5JezWgevNyl05XOo= 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-328-_DexzrpoNwewXgEa8Hgn2w-1; Wed, 25 Mar 2020 12:00:06 -0400 X-MC-Unique: _DexzrpoNwewXgEa8Hgn2w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 413AD800EBD; Wed, 25 Mar 2020 16:00:05 +0000 (UTC) Received: from ovpn-114-87.ams2.redhat.com (ovpn-114-87.ams2.redhat.com [10.36.114.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B080953AC; Wed, 25 Mar 2020 16:00:03 +0000 (UTC) Message-ID: <2b5f096a143f4dea9c9a2896913d8ca79688b00f.camel@redhat.com> Subject: Re: [PATCH net-next] net: use indirect call wrappers for skb_copy_datagram_iter() From: Paolo Abeni To: Willem de Bruijn Cc: Eric Dumazet , "David S . Miller" , netdev , Eric Dumazet Date: Wed, 25 Mar 2020 17:00:02 +0100 In-Reply-To: References: <20200325022321.21944-1-edumazet@google.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.5 (3.32.5-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 2020-03-25 at 10:55 -0400, Willem de Bruijn wrote: > On the UDP front this reminded me of another indirect function call > without indirect call wrapper: getfrag in __ip_append_data. > > That is called for each datagram once per linear + once per page. That > said, the noise in my quick RR test was too great to measure any > benefit from the following. Why an RR test ? I think you should be able to measure some raw tput improvement with large UDP GSO write towards a blackhole dst/or dropping ingress pkts with XDP (just to be sure the bottle-neck is on the sender side). > Paolo, did you happen to also look at that > when introducing the indirect callers? Seems like it won't hurt to > add. Nope, sorry I haven't experimented that. For the record, I have 2 others item on my list, I hope to have time to process some day: the ingress dst->input and the default ->enqueue and ->dequeue Cheers, Paolo p.s. feel free to move this on a different thread, as it fit you better