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: 261201 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [IPv6:::1]) by ozlabs.org (Postfix) with ESMTP id 504D32C00F5 for ; Wed, 24 Jul 2013 06:25:49 +1000 (EST) Received: from filtteri5.pp.htv.fi (filtteri5.pp.htv.fi [213.243.153.188]) by ozlabs.org (Postfix) with ESMTP id 6F7E32C00D0 for ; Wed, 24 Jul 2013 06:25:01 +1000 (EST) 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 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 Cc: Aaro Koskinen X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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");