From owner-freebsd-stable@freebsd.org Sun Dec 16 20:12:34 2018 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C66401339BD8 for ; Sun, 16 Dec 2018 20:12:34 +0000 (UTC) (envelope-from pi@opsec.eu) Received: from fc.opsec.eu (fc.opsec.eu [IPv6:2001:14f8:200:4::4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id EFDD195416 for ; Sun, 16 Dec 2018 20:12:33 +0000 (UTC) (envelope-from pi@opsec.eu) Received: from pi by fc.opsec.eu with local (Exim 4.91 (FreeBSD)) (envelope-from ) id 1gYcm6-0006NS-7u for freebsd-stable@freebsd.org; Sun, 16 Dec 2018 21:12:30 +0100 Resent-From: Kurt Jaeger Resent-Date: Sun, 16 Dec 2018 21:12:30 +0100 Resent-Message-ID: <20181216201230.GQ25709@fc.opsec.eu> Resent-To: freebsd-stable@freebsd.org Received: from mx2.freebsd.org ([8.8.178.116]:62358) by fc.opsec.eu with esmtp (Exim 4.91 (FreeBSD)) (envelope-from ) id 1gYbCL-0006HX-2Z for pi@fc.opsec.eu; 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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=OtCVCfXd6nqIqR+MAAArC1mJ64fkNcr3K3WJ4WlO7Ow=; b=rJR6o2LioMC4/f4g9K6wyB2f4IGY3UaJ/XrVsyaYJNTCXOxVDMqBkhGSuhpzHKCTiD GAQayveS8OhXxLtZaX+BRKFjFwuU0sSrwDIzjfrTPnzIqqIBtLJDdLp+Ywv4smApGOIb F506cxYtyk+qoGYb7wgA5J1n0eBTyXaN9eemOIEjpYsj5DhU+J90gbkRACqBGph0wDbA Ow1wl5ZEkyyIQoWOxLHQrRwTP/DV8RLmnGdFsL+L4uZ4xprGGUIhgQKXTqSM9WG/sbv0 7qGhVWsFbOtYcHVZpFpY0QPy5Ls491X8s/yBiifrSyol25DE/aT9qxMmuN1T4zrgYSv2 7I+g== X-Gm-Message-State: AA+aEWYPYy0hOUGSDTONZCUB7Xi0wNr+tmOInO0U7l/wt1EeenF6gUO3 SJ4T1R2pO66JjI8PZk1JIIWCz7AqLaWWOs/6qGcjI8JI73E= X-Google-Smtp-Source: AFSGD/VIxMABY7rTTzaAFmSTdRoQFbntBzXLcpHDtxpEUmNmR0FuudS1vZdC6XQqaLiQXO+xIM7glXOvJv+WYPmGBQg= X-Received: by 2002:aed:3eac:: with SMTP id n41mr10736970qtf.196.1544985073874; Sun, 16 Dec 2018 10:31:13 -0800 (PST) MIME-Version: 1.0 References: <20181216164446.GE63752@home.opsec.eu> In-Reply-To: <20181216164446.GE63752@home.opsec.eu> From: Matt Garber Date: Sun, 16 Dec 2018 13:31:03 -0500 Message-ID: Subject: Re: HEADS UP: TCP CUBIC Broken on 12.0-RELEASE/STABLE To: Kurt Jaeger X-Rspamd-Queue-Id: 1A1A4919F4 X-Spamd-Bar: ------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=p4GMgbyn; dmarc=pass (policy=none) header.from=gmail.com; spf=softfail (mx1.freebsd.org: 96.47.72.132 is neither permitted nor denied by domain of mattgarber@gmail.com) smtp.mailfrom=mattgarber@gmail.com X-Spamd-Result: default: False [-7.30 / 15.00]; FORGED_RECIPIENTS_FORWARDING(0.00)[]; FORWARDED(0.00)[pi@localmail.freebsd.org]; FREEMAIL_FROM(0.00)[gmail.com]; SPF_FAIL_FORWARDING(0.00)[]; R_SPF_SOFTFAIL(0.00)[~all]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(0.00)[gmail.com,none]; MX_GOOD(-0.01)[cached: alt3.gmail-smtp-in.l.google.com]; DMARC_POLICY_ALLOW_WITH_FAILURES(-0.50)[]; NEURAL_HAM_SHORT(-0.94)[-0.935,0]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+,1:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:11403, ipnet:96.47.64.0/20, country:US]; TAGGED_FROM(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com.dwl.dnswl.org : 127.0.5.0]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; RCVD_COUNT_FIVE(0.00)[5]; FROM_HAS_DN(0.00)[]; FORGED_RECIPIENTS(0.00)[pi@freebsd.org,pi@fc.opsec.eu]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; IP_SCORE(-3.55)[ip: (-9.26), ipnet: 96.47.64.0/20(-4.63), asn: 11403(-3.80), country: US(-0.08)]; RCPT_COUNT_ONE(0.00)[1] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 Dec 2018 20:12:35 -0000 On Sun, Dec 16, 2018 at 11:44 AM Kurt Jaeger wrote: > Will CUBIC be used if the system is running 12.0, or does it only happen > if one actively configures the use of the algorithm ? > > Can the use be detected somehow ? > This only happens if someone explicitly configured the use of the alternate CC: by setting "cc_cubic_load=YES" in loader.conf{.local}, and setting "net.inet.tcp.cc.algorithm=cubic" in sysctl.conf. These values deviate from the default FreeBSD use of newreno, so they must have been set by the admin at some point, either in a previous release that's been upgraded over time (like my original discovery), or on a fresh 12.0-RELEASE/STABLE box using some kind of configuration control or manual setup. Simplistic instructions to check on a running system could use `sysctl net.inet.tcp.cc.algorithm` and check that return value for 'cubic'; if it returns 'newreno', it's the default, and if it returns something else (e.g., 'htcp') they're also unaffected in this particular case. If they are using cubic, it should either be changed in loader.conf{.local} and sysctl.conf back to newreno or another CC prior to upgrading to 12.0-RELEASE/STABLE, or they should wait until the Errata Notice is hopefully released with the reverted change. Otherwise they'll encounter the same network connection stalls and problems. -- Thanks, -Matt Garber