From patchwork Tue Jul 23 20:24:37 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaro Koskinen X-Patchwork-Id: 2832194 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id D9797C0319 for ; Tue, 23 Jul 2013 20:25:10 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F098020315 for ; Tue, 23 Jul 2013 20:25:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17F942030A for ; Tue, 23 Jul 2013 20:25:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934413Ab3GWUZA (ORCPT ); Tue, 23 Jul 2013 16:25:00 -0400 Received: from filtteri5.pp.htv.fi ([213.243.153.188]:35400 "EHLO filtteri5.pp.htv.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934343Ab3GWUY6 (ORCPT ); Tue, 23 Jul 2013 16:24:58 -0400 Received: from localhost (localhost [127.0.0.1]) by filtteri5.pp.htv.fi (Postfix) with ESMTP id 77D515A6D84; Tue, 23 Jul 2013 23:24:57 +0300 (EEST) X-Virus-Scanned: Debian amavisd-new at pp.htv.fi Received: from smtp6.welho.com ([213.243.153.40]) by localhost (filtteri5.pp.htv.fi [213.243.153.188]) (amavisd-new, port 10024) with ESMTP id GzdwJO7N20Rq; Tue, 23 Jul 2013 23:24:52 +0300 (EEST) Received: from blackmetal.pp.htv.fi (cs181064211.pp.htv.fi [82.181.64.211]) by smtp6.welho.com (Postfix) with ESMTP id 686295BC006; Tue, 23 Jul 2013 23:24:52 +0300 (EEST) From: Aaro Koskinen To: "Rafael J. Wysocki" , Viresh Kumar , Benjamin Herrenschmidt , Nick Piggin , linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: Aaro Koskinen Subject: [PATCH 1/3] cpufreq: pmac64: speed up frequency switch Date: Tue, 23 Jul 2013 23:24:37 +0300 Message-Id: <1374611079-28091-1-git-send-email-aaro.koskinen@iki.fi> X-Mailer: git-send-email 1.8.3.2 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some functions on switch path use msleep() which is inaccurate, and depends on HZ. With HZ=100 msleep(1) takes actually over ten times longer. Using usleep_range() we get more accurate sleeps. I measured the "pfunc_slewing_done" polling to take 300us at max (on 2.3GHz dual-processor Xserve G5), so using 500us sleep there should be fine. With the patch, g5_switch_freq() duration drops from ~50ms to ~10ms on Xserve with HZ=100. Signed-off-by: Aaro Koskinen Acked-by: Viresh Kumar --- drivers/cpufreq/pmac64-cpufreq.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/pmac64-cpufreq.c b/drivers/cpufreq/pmac64-cpufreq.c index 7ba4234..674807d 100644 --- a/drivers/cpufreq/pmac64-cpufreq.c +++ b/drivers/cpufreq/pmac64-cpufreq.c @@ -141,7 +141,7 @@ static void g5_vdnap_switch_volt(int speed_mode) pmf_call_one(pfunc_vdnap0_complete, &args); if (done) break; - msleep(1); + usleep_range(1000, 1000); } if (done == 0) printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n"); @@ -240,7 +240,7 @@ static void g5_pfunc_switch_volt(int speed_mode) if (pfunc_cpu1_volt_low) pmf_call_one(pfunc_cpu1_volt_low, NULL); } - msleep(10); /* should be faster , to fix */ + usleep_range(10000, 10000); /* should be faster , to fix */ } /* @@ -285,7 +285,7 @@ static int g5_pfunc_switch_freq(int speed_mode) pmf_call_one(pfunc_slewing_done, &args); if (done) break; - msleep(1); + usleep_range(500, 500); } if (done == 0) printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");