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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D7BCC433F5 for ; Wed, 10 Nov 2021 22:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAD7061213 for ; Wed, 10 Nov 2021 22:18:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233889AbhKJWVV (ORCPT ); Wed, 10 Nov 2021 17:21:21 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:37601 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233898AbhKJWUu (ORCPT ); Wed, 10 Nov 2021 17:20:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636582682; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=cGTOzuKgGfZcDjVsrb0vtL9uCD+1inop5sEVC7ZUv/8=; b=SmqpFDC/K+hxI1i49ub0R4LmPu84Al1kHx86mbM4btf/dLGbYgwwtA22aOFiLC5iQgaZxQ hpMFBenGlcyNMIsEYIM+V2xKDbIPZFraIm9kZMwsjtLbg1mtcwYVaGOZhBZ5t4m8nlE3zb XQx0lSj/0DyM9GV5VJDNpEotZkeI+04= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-151-ZZ0Wl7hGMkS2L8UXoE3GKg-1; Wed, 10 Nov 2021 17:17:56 -0500 X-MC-Unique: ZZ0Wl7hGMkS2L8UXoE3GKg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BC4EB18D6A25; Wed, 10 Nov 2021 22:17:54 +0000 (UTC) Received: from llong.com (unknown [10.22.17.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id C344D5E26A; Wed, 10 Nov 2021 22:17:47 +0000 (UTC) From: Waiman Long To: John Stultz , Thomas Gleixner , Stephen Boyd Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Cassio Neri , Linus Walleij , Colin Ian King , Frederic Weisbecker , Feng Tang , "Paul E. McKenney" , Waiman Long Subject: [PATCH 0/2] clocksource: Avoid incorrect hpet fallback Date: Wed, 10 Nov 2021 17:17:30 -0500 Message-Id: <20211110221732.272986-1-longman@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It was found that when an x86 system was being stressed by running various different benchmark suites, the clocksource watchdog might occasionally mark TSC as unstable and fall back to hpet which will have a signficant impact on system performance. The current watchdog clocksource skew threshold of 50us is found to be insufficient. So it is changed back to 100us before commit 2e27e793e280 ("clocksource: Reduce clocksource-skew threshold") in patch 1. Patch 2 adds a Kconfig option to allow kernel builder to control the actual threshold to be used. Waiman Long (2): clocksource: Avoid accidental unstable marking of clocksources clocksource: Add a Kconfig option for WATCHDOG_MAX_SKEW kernel/time/Kconfig | 9 ++++++ kernel/time/clocksource.c | 58 ++++++++++++++++++++++++++++++--------- 2 files changed, 54 insertions(+), 13 deletions(-) -- 2.27.0