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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 8FE42C282DD for ; Thu, 23 May 2019 11:25:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 687E320851 for ; Thu, 23 May 2019 11:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730471AbfEWLZq (ORCPT ); Thu, 23 May 2019 07:25:46 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:41719 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729962AbfEWLZq (ORCPT ); Thu, 23 May 2019 07:25:46 -0400 Received: by mail-lj1-f193.google.com with SMTP id q16so5094083ljj.8 for ; Thu, 23 May 2019 04:25:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=SrYXsYajuhxHoYUyiFBd8Tl+QmrENDXMAS1vXU2GDmk=; b=hmlN/tseKmC3wbuOAd1VY6S5uNt32yn+f1l83fQWeiKKEPTZuXkpx/s7xSR0kVID+2 kc1XHfoQPOsu66IoR1RjNksvsuimhQN/4cF3YWZHNJ1H0EB+dUKk8nA93rg885GRZ2Sj L/7IrF9t15V58k+v1HCLfeMBd4ZsDne1pGsxdkZCBiN4O6jOv8yPJHeEvwdxPuTPDX1t RFcUtICAuboEs6naTqXTJLSW7lk2tYlBX8VhtUhrj9VlNSyZaAYjy74Ujy7sirI62zVn QBL3OteX+i5m8Cskkh47Z4i1EyI2o23pENa/ULsBKQhZh9Y7ydOLPCJW1a3qhryH4Nza NwAQ== X-Gm-Message-State: APjAAAXNDj9dm5zjgXYebRR/u0RySa68evCKrsHJZadURZpd8MGM5gQ8 oNGNSfdNQksNvGVAZEMyS2aXzg== X-Google-Smtp-Source: APXvYqyH2WNXzf0sY4Zfc0VvB7Ym06Z0i+3CkgkwpnAjAUzvRTCKfo/WBlR7bk3l2r85cxF8ZGh21w== X-Received: by 2002:a2e:9acb:: with SMTP id p11mr19382428ljj.129.1558610744451; Thu, 23 May 2019 04:25:44 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk (borgediget.toke.dk. [85.204.121.218]) by smtp.gmail.com with ESMTPSA id i74sm6064892lfg.78.2019.05.23.04.25.43 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 23 May 2019 04:25:43 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 953EF1800B1; Thu, 23 May 2019 13:25:42 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Toshiaki Makita , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend Cc: Toshiaki Makita , netdev@vger.kernel.org, xdp-newbies@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH bpf-next 3/3] veth: Support bulk XDP_TX In-Reply-To: <1558609008-2590-4-git-send-email-makita.toshiaki@lab.ntt.co.jp> References: <1558609008-2590-1-git-send-email-makita.toshiaki@lab.ntt.co.jp> <1558609008-2590-4-git-send-email-makita.toshiaki@lab.ntt.co.jp> X-Clacks-Overhead: GNU Terry Pratchett Date: Thu, 23 May 2019 13:25:42 +0200 Message-ID: <87zhnd1kg9.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Toshiaki Makita writes: > This improves XDP_TX performance by about 8%. > > Here are single core XDP_TX test results. CPU consumptions are taken > from "perf report --no-child". > > - Before: > > 7.26 Mpps > > _raw_spin_lock 7.83% > veth_xdp_xmit 12.23% > > - After: > > 7.84 Mpps > > _raw_spin_lock 1.17% > veth_xdp_xmit 6.45% > > Signed-off-by: Toshiaki Makita > --- > drivers/net/veth.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index 52110e5..4edc75f 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -442,6 +442,23 @@ static int veth_xdp_xmit(struct net_device *dev, int n, > return ret; > } > > +static void veth_xdp_flush_bq(struct net_device *dev) > +{ > + struct xdp_tx_bulk_queue *bq = this_cpu_ptr(&xdp_tx_bq); > + int sent, i, err = 0; > + > + sent = veth_xdp_xmit(dev, bq->count, bq->q, 0); Wait, veth_xdp_xmit() is just putting frames on a pointer ring. So you're introducing an additional per-cpu bulk queue, only to avoid lock contention around the existing pointer ring. But the pointer ring is per-rq, so if you have lock contention, this means you must have multiple CPUs servicing the same rq, no? So why not just fix that instead? -Toke From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f195.google.com ([209.85.208.195]:39539 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729863AbfEWLZq (ORCPT ); Thu, 23 May 2019 07:25:46 -0400 Received: by mail-lj1-f195.google.com with SMTP id a10so5107719ljf.6 for ; Thu, 23 May 2019 04:25:45 -0700 (PDT) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= Subject: Re: [PATCH bpf-next 3/3] veth: Support bulk XDP_TX In-Reply-To: <1558609008-2590-4-git-send-email-makita.toshiaki@lab.ntt.co.jp> References: <1558609008-2590-1-git-send-email-makita.toshiaki@lab.ntt.co.jp> <1558609008-2590-4-git-send-email-makita.toshiaki@lab.ntt.co.jp> Date: Thu, 23 May 2019 13:25:42 +0200 Message-ID: <87zhnd1kg9.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Sender: xdp-newbies-owner@vger.kernel.org List-ID: To: Toshiaki Makita , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend Cc: netdev@vger.kernel.org, xdp-newbies@vger.kernel.org, bpf@vger.kernel.org Toshiaki Makita writes: > This improves XDP_TX performance by about 8%. > > Here are single core XDP_TX test results. CPU consumptions are taken > from "perf report --no-child". > > - Before: > > 7.26 Mpps > > _raw_spin_lock 7.83% > veth_xdp_xmit 12.23% > > - After: > > 7.84 Mpps > > _raw_spin_lock 1.17% > veth_xdp_xmit 6.45% > > Signed-off-by: Toshiaki Makita > --- > drivers/net/veth.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index 52110e5..4edc75f 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -442,6 +442,23 @@ static int veth_xdp_xmit(struct net_device *dev, int n, > return ret; > } > > +static void veth_xdp_flush_bq(struct net_device *dev) > +{ > + struct xdp_tx_bulk_queue *bq = this_cpu_ptr(&xdp_tx_bq); > + int sent, i, err = 0; > + > + sent = veth_xdp_xmit(dev, bq->count, bq->q, 0); Wait, veth_xdp_xmit() is just putting frames on a pointer ring. So you're introducing an additional per-cpu bulk queue, only to avoid lock contention around the existing pointer ring. But the pointer ring is per-rq, so if you have lock contention, this means you must have multiple CPUs servicing the same rq, no? So why not just fix that instead? -Toke