Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933114AbaLJU3R (ORCPT ); Wed, 10 Dec 2014 15:29:17 -0500 Received: from mga02.intel.com ([134.134.136.20]:7047 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932806AbaLJU3Q (ORCPT ); Wed, 10 Dec 2014 15:29:16 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,553,1413270000"; d="scan'208";a="621787304" Date: Wed, 10 Dec 2014 12:28:49 -0800 From: Kristen Carlson Accardi To: Ethan Zhao Cc: , , , , , , , , Subject: Re: [PATCH 2/2 V9] intel_pstate: add kernel parameter to force loading. Message-ID: <20141210122849.17d258d8@kcaccard-desk.amr.corp.intel.com> In-Reply-To: <1418089399-9310-1-git-send-email-ethan.zhao@oracle.com> References: <1418089399-9310-1-git-send-email-ethan.zhao@oracle.com> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.24; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Dec 2014 10:43:19 +0900 Ethan Zhao wrote: > To force loading on Oracle Sun X86 servers, provide one kernel command line > parameter > > intel_pstate = force > > For those who be aware of the risk of no power capping capabily working and > try to get better performance with this driver. > > Signed-off-by: Ethan Zhao > Tested-by: Alexey Kodanev > Reviewed-by: Linda Knippers Acked-by: Kristen Carlson Accardi > --- > v2: change to hardware vendor specific naming parameter. > v4: refine code and doc. > v5&v6: fix a typo in doc. > v7: change enum PCC to PPC. > v8: change the name of kernel command line parameter to generic one. > v9: refine doc > > Documentation/kernel-parameters.txt | 5 +++++ > drivers/cpufreq/intel_pstate.c | 6 +++++- > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index 479f332..7d0983e 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -1446,6 +1446,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > disable > Do not enable intel_pstate as the default > scaling driver for the supported processors > + force > + Enable intel_pstate on systems that prohibit it by default > + in favor of acpi-cpufreq. Forcing the intel_pstate driver > + instead of acpi-cpufreq may disable platform features, such > + as thermal controls and power capping, that rely on ACPI > + P-States information being indicated to OSPM and therefore > + should be used with caution. This option does not work with > + processors that aren't supported by the intel_pstate driver > + or on platforms that use pcc-cpufreq instead of acpi-cpufreq. > > intremap= [X86-64, Intel-IOMMU] > on enable Interrupt Remapping (default) > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index 1bb62ca..2654e13 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = { > }; > > static int __initdata no_load; > +static unsigned int force_load; > > static int intel_pstate_msrs_not_valid(void) > { > @@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void) > case PSS: > return intel_pstate_no_acpi_pss(); > case PPC: > - return intel_pstate_has_acpi_ppc(); > + return intel_pstate_has_acpi_ppc() && > + (!force_load); > } > } > > @@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str) > > if (!strcmp(str, "disable")) > no_load = 1; > + if (!strcmp(str, "force")) > + force_load = 1; > return 0; > } > early_param("intel_pstate", intel_pstate_setup); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/