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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 A8BCFC10F11 for ; Wed, 10 Apr 2019 13:01:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BE442083E for ; Wed, 10 Apr 2019 13:01:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="A5RSLA+5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732249AbfDJNBv (ORCPT ); Wed, 10 Apr 2019 09:01:51 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53808 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727178AbfDJNBu (ORCPT ); Wed, 10 Apr 2019 09:01:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Mime-Version:Content-Type:References: In-Reply-To:Date:To:From:Subject:Message-ID:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=62vhcvQ27GkXSWWf+ybPRUjOZLtXNShlpV6HdElVMDs=; b=A5RSLA+5zZVYF/Z8ewjEjwgcK Lvni0u75m+J/P/73PNsrKXFTpGwCFkXdVSLAw0LopO1YBA6yAiA6njWHdJ7k0ZFd1SMOnD7R1N3HZ U48fYzeuTiiN1zdrD/gF9+ReFP2iIBeo02Aadt+Ehw7DiYFdR0tHSFAp89a6iy37yfM0+eFqrdhbK q7nTNLNZ9qpLCOLpIXKKk2u3u0bNxvU35APhHVvV9YI6s8DyuuaChxeg9d4TSt3ynzAB4lfpg1fE3 pZBDsniCW2jpnBWyzuVr2q45OEhH0JTPqKgvlqdcLoSSiExyDD9y9IIp31wgFacbUHpqT5jiLFJ8b Jq6eqk7Tw==; Received: from 54-240-197-235.amazon.com ([54.240.197.235] helo=u3832b3a9db3152.ant.amazon.com) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hECrM-0008Rp-S5 for netdev@vger.kernel.org; Wed, 10 Apr 2019 13:01:49 +0000 Message-ID: <1506fcbbfb7ab7a1e448b7b6cbf45f703bfcc80f.camel@infradead.org> Subject: Re: Tun congestion/BQL From: David Woodhouse To: netdev@vger.kernel.org Date: Wed, 10 Apr 2019 16:01:46 +0300 In-Reply-To: <2e310fc6ee847d20dd23692fd1db733e607602f5.camel@infradead.org> References: <2e310fc6ee847d20dd23692fd1db733e607602f5.camel@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-pjLL3vpha2IaKOgFDNaG" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org --=-pjLL3vpha2IaKOgFDNaG Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-04-10 at 15:01 +0300, David Woodhouse wrote: > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1125,7 +1128,9 @@ static netdev_tx_t tun_net_xmit(struct sk_buff > *skb, struct net_device *dev) > if (tfile->flags & TUN_FASYNC) > kill_fasync(&tfile->fasync, SIGIO, POLL_IN); > tfile->socket.sk->sk_data_ready(tfile->socket.sk); > =20 > + if (!ptr_ring_empty(&tfile->tx_ring)) > + netif_stop_queue(tun->dev); > rcu_read_unlock(); > return NETDEV_TX_OK; > =20 >=20 Hm, that should be using ptr_ring_full() shouldn't it? So... --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1121,6 +1121,9 @@ static netdev_tx_t tun_net_xmit(struct s if (ptr_ring_produce(&tfile->tx_ring, skb)) goto drop; =20 + if (ptr_ring_full(&tfile->tx_ring)) + netif_stop_queue(tun->dev); + /* Notify and wake up reader process */ if (tfile->flags & TUN_FASYNC) kill_fasync(&tfile->fasync, SIGIO, POLL_IN); @@ -2229,6 +2232,7 @@ static ssize_t tun_do_read(struct tun_st consume_skb(skb); } =20 + netif_wake_queue(tun->dev); return ret; } =20 That doesn't seem to make much difference at all; it's still dropping a lot of packets because ptr_ring_produce() is returning non-zero. Socket Message Elapsed Messages =20 Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 212992 1400 10.00 7747169 0 8676.81 212992 10.00 1471769 1648.38 Making it call netif_stop_queue() when ptr_ring_produce() fails causes it to perform even worse... Socket Message Elapsed Messages =20 Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 212992 1400 10.00 1906235 0 2134.98 212992 10.00 985428 1103.68 At this point I'm mostly just confused.=20 --=-pjLL3vpha2IaKOgFDNaG Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCECow ggUcMIIEBKADAgECAhEA4rtJSHkq7AnpxKUY8ZlYZjANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTkwMTAyMDAwMDAwWhcNMjIwMTAxMjM1 OTU5WjAkMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZyYWRlYWQub3JnMIIBIjANBgkqhkiG9w0B AQEFAAOCAQ8AMIIBCgKCAQEAsv3wObLTCbUA7GJqKj9vHGf+Fa+tpkO+ZRVve9EpNsMsfXhvFpb8 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