From patchwork Thu Apr 13 11:48:03 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 9679245 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 553A860381 for ; Thu, 13 Apr 2017 11:48:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 49F372863B for ; Thu, 13 Apr 2017 11:48:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3D48228652; Thu, 13 Apr 2017 11:48:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C846A2863B for ; Thu, 13 Apr 2017 11:48:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2638A6E2E4; Thu, 13 Apr 2017 11:48:14 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6AA486E2E4 for ; Thu, 13 Apr 2017 11:48:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: 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=WUgETL9cY9K9c0ixDhAO8x+0i9GlnPmf89rjo0+JNdA=; b=iOoR3Oa0WQvf6OhV5jhsk5+5w L36g/zeIDCzOag7VvAJm2lG5XDQH/+RIpqTAlHNjNPX+VaMYUn6AqA8yiI+Nz28m1t4JZnvGC4fos VCMgzI0u47UX2OZaes6h03HucvPuHVKqBATRemsKHQfmfBgIC0OSbdYilfF4JjZbwm4ReX8Z1Pqa+ Do4oFAfQ4iytyy7cK7GoIDcKubhegr330qqZNMsGPazzYoxhLokM7MR7v/sAFs/lMM5vMUMJiC+AT QRkrkGUj16qyLmZwYuJdki9iO9DP+EqgTSWHuqDi62IEEUqucPP+TZpGaCQoSQWfgPKreQLUxCRtf AezqOok1w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.87 #1 (Red Hat Linux)) id 1cydEM-00055b-0I; Thu, 13 Apr 2017 11:48:06 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D0463202682BA; Thu, 13 Apr 2017 13:48:03 +0200 (CEST) Date: Thu, 13 Apr 2017 13:48:03 +0200 From: Peter Zijlstra To: Martin Peres Message-ID: <20170413114803.poziwglvrzbmtmvb@hirez.programming.kicks-ass.net> References: <20170412123134.GD5680@worktop> <9fc50a4b-da78-5e18-8fed-3bf91a7091a7@linux.intel.com> <20170412143222.5523ltuiz5kdmdl7@hirez.programming.kicks-ass.net> <8b94e683-3d09-d5dc-cfd1-746f179f3678@linux.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8b94e683-3d09-d5dc-cfd1-746f179f3678@linux.intel.com> User-Agent: NeoMutt/20170113 (1.7.2) Cc: "intel-gfx@lists.freedesktop.org" , Thomas Gleixner , "pasha.tatashin@oracle.com" Subject: Re: [Intel-gfx] freedesktop bug id: 100548, bisected to sched/clock commit X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP On Wed, Apr 12, 2017 at 05:49:53PM +0300, Martin Peres wrote: > Good to know. Is there a way to disable this behaviour, as a workaround for > our CI system until a proper fix lands? We already pushed locally the revert > for this patch, but that may affect other platforms which do not exhibit the > problem. Blergh, so the patch is correct, but the __gtod_offset calculation is fed with absolute crap numbers due to 'circumstances' and then using it ends up being worse than not using it. Something like the below could be a work-around, but let me see if I can't fix things better. --- arch/x86/kernel/tsc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 714dfba..8ab883a 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -374,6 +374,8 @@ static int __init tsc_setup(char *str) tsc_clocksource_reliable = 1; if (!strncmp(str, "noirqtime", 9)) no_sched_irq_time = 1; + if (!strcmp(str, "unstable")) + mark_tsc_unstable("boot parameter"); return 1; }