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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1FF35C433E0 for ; Thu, 28 Jan 2021 22:56:12 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C377C64DE8 for ; Thu, 28 Jan 2021 22:56:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C377C64DE8 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.77489.140357 (Exim 4.92) (envelope-from ) id 1l5GCj-0004V1-Dd; Thu, 28 Jan 2021 22:55:57 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 77489.140357; Thu, 28 Jan 2021 22:55:57 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l5GCj-0004Uu-Ag; Thu, 28 Jan 2021 22:55:57 +0000 Received: by outflank-mailman (input) for mailman id 77489; Thu, 28 Jan 2021 22:55:56 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1l5GCi-0004Up-83 for xen-devel@lists.xenproject.org; Thu, 28 Jan 2021 22:55:56 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 404bab29-d9f8-4ad0-bb1f-7eadbfd1199d; Thu, 28 Jan 2021 22:55:54 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1E314AC60; Thu, 28 Jan 2021 22:55:54 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 404bab29-d9f8-4ad0-bb1f-7eadbfd1199d X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611874554; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=k0f8Wp0+uXKvQs+GP87iM2ln1QnlEbp/tZnieWpA6V4=; b=DXzuXvPPIpqIfAiyzBcBbOSm8nDTtEE9JjB1+Sp5YQdtUz8PsvqIoDIvyPCIBA2cY6XDVW FsOtQ0kxvanFcsTVLmSDLb1kS+TFKNlMaOpAN6POBkMFsf4fngLxAhc9OBFZatbYeNTy4x xOGqkdcTj7aKaRAS0uye5y46vpm+2p0= Message-ID: <0605f27e9e2215f5b71690dcc60d481dd630b35f.camel@suse.com> Subject: Re: [ANNOUNCE] Xen 4.15 release schedule and feature tracking From: Dario Faggioli To: "Lengyel, Tamas" , "Cooper, Andrew" , Ian Jackson , "xen-devel@lists.xenproject.org" , "committers@xenproject.org" , Tamas K Lengyel , =?UTF-8?Q?Micha=C5=82_Leszczy=C5=84ski?= Date: Thu, 28 Jan 2021 23:55:52 +0100 In-Reply-To: References: <24567.7198.846779.557032@mariner.uk.xensource.com> <24576.27654.137226.608671@mariner.uk.xensource.com> <017cd214-fce8-f8b7-7134-0a89eb45c2ac@citrix.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-hlYbpTe4hl9fEhjoOSGw" User-Agent: Evolution 3.38.3 (by Flathub.org) MIME-Version: 1.0 --=-hlYbpTe4hl9fEhjoOSGw Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2021-01-15 at 15:14 +0000, Lengyel, Tamas wrote: >=20 > > 2) "scheduler broken" bugs.=C2=A0 We've had 4 or 5 reports of Xen not > > working, > > and very little investigation on whats going on.=C2=A0 Suspicion is tha= t > > there > > might be two bugs, one with smt=3D0 on recent AMD hardware, and one > > more general "some workloads cause negative credit" and might or > > might > > not be specific to credit2 (debugging feedback differs - also might > > be 3 > > underlying issue). >=20 > We've also ran into intermittent Xen lockups requiring power-cycling > servers. We switched back to credit1 and had no issues since.=C2=A0 > Ah, that's interesting... Among the issues that I listed in my other email, when trying to do a quick summary, "only" number 1 is about Credit working when Credit2 does not. This one you're mentioning here may be the second... or it may be the same! :-O As said there, my theory so far is that there's a bug somewhere, not necessarily in scheduling code, to which the two algorithms react differently. Of course this is a theory, and I've not been able to confirm it yet (otherwise I also would have fixed the problem. :-P). But really, it would be interesting to double check if at least the symptoms are the same than the ones of the issue reported here. > Hard to tell if it was related to the scheduler or the pile of other > experimental stuff we are running with but right now we have stable > systems across the board with credit1. >=20 Well, sure, that's understandable. :-) Which is why it's tricky at times to debug these issue. In fact, I cannot reproduce them myself, and users, rightfully, move on if they found a workaround. Anyway, if at some point you decide to investigate, I'll be happy to help. Regards --=20 Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <> (Raistlin Majere) --=-hlYbpTe4hl9fEhjoOSGw Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEES5ssOj3Vhr0WPnOLFkJ4iaW4c+4FAmATQPgACgkQFkJ4iaW4 c+60bhAAnIT3DkkqxjCJ+sWv0Ehxm1WYfwkes9cweV6AogNLGOaS82nyF6KEUJXz sbJ2DpQbvJOdtHG19uFjmpJL6/MzEir8C5TJLNHdlfbHiwDbUd+YwBBlyen+F9VW Ol195A0TlzbXCN7BtweeDvy8xHuYT1ZkjCHMQ9mkr6hH2tjbgOxI8Q3uLTpJbR45 CJdIYPN7Xphe4uJMLvckCQTF4F4meyAtf19eB+jIBARtjfVUCavkUAMUjzWQ4k61 uHB0Fqm0dUOI3UoQZEkOz+NlgFaQ7LNxgSqcCXNiF8fK22VL7mAoMgptUM/C4ANw NzOmWCd44gQEX5ZyAtDKpACapA2Lfv3o+tOnZrPLKtcGCDlineSk38sZRiASmRHb ToBoVyUYGlW2U0Cdt91aM7ZghQ6P6TVDON0ldeEGRzcIVAla71qVIrr+imz9St2i W7CZMHGom/rJ7WBmbtIhkOQN2749k8mUiqGKeL44+ByY9ahGPiXNJAm+TlSFDVyX fuZiq2t2bGHqnjrY022IYWzBP2nxVJOotv3QgaVK/LucmRghMPe+Q0ILWDypePHV YGCQPCCk4DaDjlxVzA5xipbF1QqjzAA7ht3nu1hBOl13NFygDK3XY5fBwlsUG0c/ 99Fpb5gsdNqt/LnVhNJ1LvNYXAiONeHLfuUanTHCHNUvPUS5sMU= =pX7N -----END PGP SIGNATURE----- --=-hlYbpTe4hl9fEhjoOSGw--