Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937470AbdLSDYj (ORCPT ); Mon, 18 Dec 2017 22:24:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:50742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937357AbdLSDYW (ORCPT ); Mon, 18 Dec 2017 22:24:22 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2036C2191C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=frederic@kernel.org From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Peter Zijlstra , Chris Metcalf , Thomas Gleixner , Luiz Capitulino , Christoph Lameter , "Paul E . McKenney" , Ingo Molnar , Wanpeng Li , Mike Galbraith , Rik van Riel Subject: [PATCH 5/5] sched/isolation: Document "nohz_offload" flag Date: Tue, 19 Dec 2017 04:23:58 +0100 Message-Id: <1513653838-31314-6-git-send-email-frederic@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1513653838-31314-1-git-send-email-frederic@kernel.org> References: <1513653838-31314-1-git-send-email-frederic@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1560 Lines: 39 Document the interface to offload the 1Hz scheduler tick in full dynticks mode. Also improve the comment about the existing "nohz" flag in order to differentiate its behaviour. Signed-off-by: Frederic Weisbecker Cc: Chris Metcalf Cc: Christoph Lameter Cc: Luiz Capitulino Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Wanpeng Li Cc: Ingo Molnar --- Documentation/admin-guide/kernel-parameters.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1683107..fcc5fd9 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1745,7 +1745,12 @@ specified in the flag list (default: domain): nohz - Disable the tick when a single task runs. + Disable the tick when a single task runs. A residual 1Hz + tick remains to maintain scheduler stats alive. + nohz_offload + Like nohz but the residual 1Hz tick is offloaded to + housekeeping CPUs, leaving the CPU free of any tick if + nothing else requests it. domain Isolate from the general SMP balancing and scheduling algorithms. Note that performing domain isolation this way -- 2.7.4