From nobody Tue Apr 7 00:20:29 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4005DC433FE for ; Sun, 9 Oct 2022 05:12:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229811AbiJIFMY (ORCPT ); Sun, 9 Oct 2022 01:12:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbiJIFMV (ORCPT ); Sun, 9 Oct 2022 01:12:21 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FDFD2A26D for ; Sat, 8 Oct 2022 22:12:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1665292340; x=1696828340; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=GwYosVc5vcm+WIpP6B82f0V3owyyyFeqQBnkDnFRTwI=; b=cknz/3v3jui429OLbKSmK7m8fcg931Enyz/M4/+NYMGMxZPbON054IqI 7hmgxCYNjIZft/K16yPsenGyk7+OVbq6DpDuwFG1drKB8lAF4LoPhoqj4 qTU1yOJvmFjwHmGgFOC+Gw61s/Aft5C9suRXbulIRLpNjIvsw1edJUrzZ xB5JkVCSfYucU4HySp1lHLvwShXCMBYzO5KHda2W+0UtTgJPOwq+jS99d pRZuHoX5W/7iZTnJm3u/0+utC3Rd4Y7swGB9Kq1Pyoif3DFnlEmJ3naft 0q9JY/ETH4ZlQOuuissqNEyE2/SQWptotb/DRYf3lQviTScpE1n8kyGBf w==; X-IronPort-AV: E=McAfee;i="6500,9779,10494"; a="305612367" X-IronPort-AV: E=Sophos;i="5.95,170,1661842800"; d="scan'208";a="305612367" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Oct 2022 22:12:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10494"; a="954540165" X-IronPort-AV: E=Sophos;i="5.95,170,1661842800"; d="scan'208";a="954540165" Received: from feng-clx.sh.intel.com ([10.238.200.228]) by fmsmga005.fm.intel.com with ESMTP; 08 Oct 2022 22:12:16 -0700 From: Feng Tang To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H . Peter Anvin" , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org Cc: rui.zhang@intel.com, tim.c.chen@intel.com, Xiongfeng Wang , Feng Tang , Yu Liao Subject: [PATCH] x86/tsc: Extend the watchdog check exemption to 4S/8S machine Date: Sun, 9 Oct 2022 13:12:09 +0800 Message-Id: <20221009051209.393377-1-feng.tang@intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There is report again that the tsc clocksource on a 4 sockets x86 Skylake server was wrongly judged as 'unstable' by 'jiffies' watchdog, and disabled [1]. Also we got silimar reports on 8 sockets platform from internal test. Commit b50db7095fe0 ("x86/tsc: Disable clocksource watchdog for TSC on qualified platorms") was introduce to deal with these false alarms of tsc unstable issues, covering qualified platforms for 2 sockets or smaller ones. Extend the exemption also to 4/8 sockets to fix the issue. Rui also proposed another way to disable 'jiffies' as clocksource watchdog [2], which can also solve this specific problem in an architecture independent way, with one limitation that some tsc false alarms are reported by other watchdogs like HPET in post-boot time, while 'jiffies' is mostly used in boot phase before hardware clocksources are initialized. [1]. https://lore.kernel.org/all/9d3bf570-3108-0336-9c52-9bee15767d29@huawe= i.com/ [2]. https://lore.kernel.org/all/bd5b97f89ab2887543fc262348d1c7cafcaae536.c= amel@intel.com/ Reported-by: Yu Liao Tested-by: Yu Liao Signed-off-by: Feng Tang --- arch/x86/kernel/tsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index cafacb2e58cc..b4ea79cb1d1a 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1217,7 +1217,7 @@ static void __init check_system_tsc_reliable(void) if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && boot_cpu_has(X86_FEATURE_NONSTOP_TSC) && boot_cpu_has(X86_FEATURE_TSC_ADJUST) && - nr_online_nodes <=3D 2) + nr_online_nodes <=3D 8) tsc_disable_clocksource_watchdog(); } =20 --=20 2.34.1