From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755972AbaE3R4g (ORCPT ); Fri, 30 May 2014 13:56:36 -0400 Received: from mga09.intel.com ([134.134.136.24]:41025 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751525AbaE3R4f (ORCPT ); Fri, 30 May 2014 13:56:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,942,1392192000"; d="scan'208";a="549040344" Subject: Re: [RFC PATCH] crypto: crc32c-pclmul - Use pmovzxdq to shrink K_table From: Tim Chen To: Dave Jones , "dirk.brandewie@gmail.com" Cc: George Spelvin , herbert@gondor.apana.org.au, james.guilford@intel.com, JBeulich@suse.com, linux-kernel@vger.kernel.org, Jacob jun Pan In-Reply-To: <20140530011636.GA31694@redhat.com> References: <20140529235432.19207.qmail@ns.horizon.com> <1401412036.2970.459.camel@schen9-DESK> <20140530011636.GA31694@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 30 May 2014 10:56:32 -0700 Message-ID: <1401472592.2970.483.camel@schen9-DESK> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-05-29 at 21:16 -0400, Dave Jones wrote: > On Thu, May 29, 2014 at 06:07:16PM -0700, Tim Chen wrote: > > On Thu, 2014-05-29 at 19:54 -0400, George Spelvin wrote: > > > Sorry for the delay; my Ivy Bridge test machine isn't in my > > > office and getting to the console to tweak the BIOS is a > > > bit of a bother. > > > > > > Anyway, i7-4930K, turbo boost & hyperthreading disabled, > > > $ cat /sys/devices/system/cpu/cpu?/cpufreq/scaling_governor > > > performance > > > performance > > > performance > > > performance > > > performance > > > performance > > > > > > Oddly, though, CPU speed still seems to be fluctuating: > > > $ grep MHz /proc/cpuinfo > > > cpu MHz : 1255.875 > > > cpu MHz : 3168.375 > > > cpu MHz : 3062.125 > > > cpu MHz : 1468.375 > > > cpu MHz : 1309.000 > > > cpu MHz : 2212.125 > > > $ grep MHz /proc/cpuinfo > > > cpu MHz : 1255.875 > > > cpu MHz : 2690.250 > > > cpu MHz : 1255.875 > > > cpu MHz : 2530.875 > > > cpu MHz : 2212.125 > > > cpu MHz : 1521.500 > > > > This is odd. On my Ivy Bridge system the CPU speed from /proc/cpuinfo > > is at max freq once I set the performance governor. > > The numbers above almost look like > > the cpu frequency is fluctuating and an average is taken. > > What version of the kernel are you running? Is > > CONFIG_CPU_FREQ_GOV_PERFORMANCE compiled in? > > > > Does /sys/devices/system/cpu/cpu?/cpufreq/scaling_cur_freq > > also changes? > > > > Can you check what are the available governors in your system > > and available frequencies? > > > > cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors > > cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies > > > > If userspace governor is available, you can try set the governor > > to userspace, then pin frequency to 3400 MHz (assuming that's your > > max) with command like: > > intel_pstate overrides any governor choice you make through sysfs. > > Dave > Dirk, Wonder if this the right behavior for intel_pstate that when I set the governor to performance, intel_pstate driver still adjusts the cpu frequencies around? Turbotstat also confirms that the frequencies are not at max, even though the max_perf_pct and min_perf_pct are both set at 100. I ran on my HSW system with 3.15-rc7 kernel and see similar issue that Geroge reported. It is really a pain when we need to do performance benchmarking and need to have a constant cpu frequency. Thanks. Tim