From patchwork Mon Apr 3 21:54:12 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 9660659 X-Patchwork-Delegate: rjw@sisk.pl 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 E92576032D for ; Mon, 3 Apr 2017 21:54:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D9E672817F for ; Mon, 3 Apr 2017 21:54:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CDC9428488; Mon, 3 Apr 2017 21:54:30 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 30F982817F for ; Mon, 3 Apr 2017 21:54:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751279AbdDCVy3 (ORCPT ); Mon, 3 Apr 2017 17:54:29 -0400 Received: from ozlabs.org ([103.22.144.67]:34019 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751210AbdDCVy3 (ORCPT ); Mon, 3 Apr 2017 17:54:29 -0400 Received: by ozlabs.org (Postfix, from userid 1010) id 3vxm8z4XVhz9s7r; Tue, 4 Apr 2017 07:54:27 +1000 (AEST) From: Anton Blanchard To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, svaidy@linux.vnet.ibm.com, ego@linux.vnet.ibm.com, rjw@rjwysocki.net, daniel.lezcano@linaro.org, npiggin@gmail.com Cc: linuxppc-dev@lists.ozlabs.org, linux-pm@vger.kernel.org Subject: [PATCH 1/3] cpuidle: powernv: Don't bounce between low and very low thread priority Date: Tue, 4 Apr 2017 07:54:12 +1000 Message-Id: <20170403215414.16951-1-anton@ozlabs.org> X-Mailer: git-send-email 2.11.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Anton Blanchard The core of snooze_loop() continually bounces between low and very low thread priority. Changing thread priorities is an expensive operation that can negatively impact other threads on a core. All CPUs that can run PowerNV support very low priority, so we can avoid the change completely. Signed-off-by: Anton Blanchard Reviewed-by: Vaidyanathan Srinivasan --- drivers/cpuidle/cpuidle-powernv.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index cda8f62d555b..9d9f164894eb 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -57,7 +57,6 @@ static int snooze_loop(struct cpuidle_device *dev, snooze_exit_time = get_tb() + snooze_timeout; ppc64_runlatch_off(); while (!need_resched()) { - HMT_low(); HMT_very_low(); if (snooze_timeout_en && get_tb() > snooze_exit_time) break;