From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com [209.85.220.42]) by dpdk.org (Postfix) with ESMTP id 5C01656A1 for ; Mon, 14 Dec 2015 19:26:01 +0100 (CET) Received: by pacdm15 with SMTP id dm15so107504682pac.3 for ; Mon, 14 Dec 2015 10:26:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id; bh=UYv0rmQNb5WkzzRMOBDJtiAFsNzrnOgRZXgqvizqWeA=; b=z4tCf6kv/DCNCf556p6W6pS0QnJZ3LcFo1rRBtfc05fXwyBnArmpSrXHUHogFvEGWT 43UvBTL/fRD7RcUzX5S+m+IeIOAlbKCE5ZyvKpS4TDdDdHRNKTCJMqCVbrgxFZYzbgNU r1TKwoXK+Iwk8DrArFE+FySZwnWVWLlmFbHNVztY3ATrlY4by/q1bCL/SpT616W7VvNl nDSUWtSGg6G/pSZkkx7M/Myk6P0yXtTBMnfzwhN3aSESDh6zi0cn6uaoCiHmDZr2asjv CZgqa5kgmQtb2vjIVdtpcwflD8/yWY0rGEaq5Qq8pVmgd4oIpgcvdewoKieIu2XJkOiB TSqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=UYv0rmQNb5WkzzRMOBDJtiAFsNzrnOgRZXgqvizqWeA=; b=LtRL71vpjGKWlzfrDtOJLyeGU4fxpWl8E2yLVjMg2hK/vZzZY2Bz63xrwFO1u5Rhaa Z8PgUPPEQ2Oi3WcQH83cVqsvfXUJQLC/dfxLEDM1rhcYosn8NvIZb7CnUOuxTNnKF79W dIs+fKvZcYjb+vjoeMc2fBdiBxNIY9gqKRK/nFMO8bddq1gim5xSn9DwcLZ81S/8znKF D0yVOu7gXnfuBBuWgGp8afl6/cAok6VH5PQJ/fNBUZfdX/PUJGiJoMM9dU2Y5UdY2ZdI Upp5U1uViujvaVXeVDjY7p5nF1lJ21GLCrmrKsgz0hvC2PuRS2GxJBZpA1JCjNeHpalP D5IQ== X-Gm-Message-State: ALoCoQmKCqXbzad8ZlAwQdNbWgflmKvh0W//jCPuUJMHJab1WKdxoEVMishLJbZs+eKFQVaXpOdGO9eknhbWBhZbw0Ps3gC0xQ== X-Received: by 10.66.228.225 with SMTP id sl1mr48080836pac.63.1450117560592; Mon, 14 Dec 2015 10:26:00 -0800 (PST) Received: from xeon-e3.home.lan (static-50-53-82-155.bvtn.or.frontiernet.net. [50.53.82.155]) by smtp.gmail.com with ESMTPSA id f5sm44355491pas.8.2015.12.14.10.25.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 14 Dec 2015 10:25:59 -0800 (PST) From: Stephen Hemminger To: helin.zhang@intel.com, konstantin.ananyev@intel.com Date: Mon, 14 Dec 2015 10:26:07 -0800 Message-Id: <1450117567-12173-1-git-send-email-stephen@networkplumber.org> X-Mailer: git-send-email 2.1.4 Cc: dev@dpdk.org, "Charles \(Chas\) Williams" Subject: [dpdk-dev] [PATCH] nohz: disable traceback on NO_HZ warning X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Dec 2015 18:26:01 -0000 From: "Charles (Chas) Williams" A NO_HZ_FULL kernel needs to have a stable clock source like a non-stop (or invariant) TSC. Unfortunately, this CPU feature/flag isn't advertised by most hypervisors because they want the ability to migrate or save virtual machines which would affect the TSC. This means that a kernel with NO_HZ_FULL configured would often generate a kernel traceback on boot which causes users to generate false alarms. NO_HZ_FULL is an optimization not a hard requirement. Keep the message, just lose the traceback. Signed-off-by: Charles (Chas) Williams Signed-off-by: Stephen Hemminger --- kernel/time/tick-sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 7c7ec45..2e1c90c 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -188,8 +188,8 @@ static bool can_stop_full_tick(void) * Don't allow the user to think they can get * full NO_HZ with this machine. */ - WARN_ONCE(tick_nohz_full_running, - "NO_HZ FULL will not work with unstable sched clock"); + if (tick_nohz_full_running) + pr_notice_once("NO_HZ FULL will not work with unstable sched clock\n"); return false; } #endif -- 2.1.4