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Date: Wed, 16 Jan 2013 20:20:08 +0800 From: Zhang Rui <rui.zhang@...el.com> To: Jacob Pan <jacob.jun.pan@...ux.intel.com> Cc: Linux PM <linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Rafael Wysocki <rafael.j.wysocki@...el.com>, Len Brown <len.brown@...el.com>, Thomas Gleixner <tglx@...utronix.de>, "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>, Joe Perches <joe@...ches.com>, Rob Landley <rob@...dley.net>, Arjan van de Ven <arjan@...ux.intel.com>, Paul McKenney <paulmck@...ux.vnet.ibm.com> Subject: Re: [PATCH v6 3/3] PM: Introduce Intel PowerClamp Driver On Wed, 2013-01-16 at 20:18 +0800, Zhang Rui wrote: > Hi, Jacob, > > On Fri, 2013-01-04 at 03:12 -0800, Jacob Pan wrote: > > Intel PowerClamp driver performs synchronized idle injection across > > all online CPUs. The goal is to maintain a given package level C-state > > ratio. > > > > Compared to other throttling methods already exist in the kernel, > > such as ACPI PAD (taking CPUs offline) and clock modulation, this is often > > more efficient in terms of performance per watt. > > > > Please refer to Documentation/thermal/intel_powerclamp.txt for more details. > > > > Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com> > > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com> > > --- > > Documentation/thermal/intel_powerclamp.txt | 307 +++++++++++ > > drivers/thermal/Kconfig | 10 + > > drivers/thermal/Makefile | 2 + > > drivers/thermal/intel_powerclamp.c | 788 ++++++++++++++++++++++++++++ > > 4 files changed, 1107 insertions(+) > > create mode 100644 Documentation/thermal/intel_powerclamp.txt > > create mode 100644 drivers/thermal/intel_powerclamp.c > > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > > index c2c77d1..7d90ab8 100644 > > --- a/drivers/thermal/Kconfig > > +++ b/drivers/thermal/Kconfig > > @@ -122,4 +122,14 @@ config DB8500_CPUFREQ_COOLING > > bound cpufreq cooling device turns active to set CPU frequency low to > > cool down the CPU. > > > > +config INTEL_POWERCLAMP > > + tristate "Intel PowerClamp idle injection driver" > > + depends on THERMAL > > + depends on X86 > > + depends on CPU_SUP_INTEL > > + help > > + Enable this to enable Intel PowerClamp idle injection driver. This > > + enforce idle time which results in more package C-state residency. The > > + user interface is exposed via generic thermal framework. > > + > > endif > > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > > index d8da683..574f5f5 100644 > > --- a/drivers/thermal/Makefile > > +++ b/drivers/thermal/Makefile > > @@ -18,3 +18,5 @@ obj-$(CONFIG_RCAR_THERMAL) += rcar_thermal.o > > obj-$(CONFIG_EXYNOS_THERMAL) += exynos_thermal.o > > obj-$(CONFIG_DB8500_THERMAL) += db8500_thermal.o > > obj-$(CONFIG_DB8500_CPUFREQ_COOLING) += db8500_cpufreq_cooling.o > > +obj-$(CONFIG_INTEL_POWERCLAMP) += intel_powerclamp.o > > + > > diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_powerclamp.c > > new file mode 100644 > > index 0000000..314b6fc > > --- /dev/null > > +++ b/drivers/thermal/intel_powerclamp.c > > @@ -0,0 +1,788 @@ > > +/* > > + * intel_powerclamp.c - package c-state idle injection > > + * > > + * Copyright (c) 2012, Intel Corporation. > > + * > > + * Authors: > > + * Arjan van de Ven <arjan@...ux.intel.com> > > + * Jacob Pan <jacob.jun.pan@...ux.intel.com> > > + * > > + * This program is free software; you can redistribute it and/or modify it > > + * under the terms and conditions of the GNU General Public License, > > + * version 2, as published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope it will be useful, but WITHOUT > > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > > + * more details. > > + * > > + * You should have received a copy of the GNU General Public License along with > > + * this program; if not, write to the Free Software Foundation, Inc., > > + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. > > + * > > + * > > + * TODO: > > + * 1. better handle wakeup from external interrupts, currently a fixed > > + * compensation is added to clamping duration when excessive amount > > + * of wakeups are observed during idle time. the reason is that in > > + * case of external interrupts without need for ack, clamping down > > + * cpu in non-irq context does not reduce irq. for majority of the > > + * cases, clamping down cpu does help reduce irq as well, we should > > + * be able to differenciate the two cases and give a quantitative > > + * solution for the irqs that we can control. perhaps based on > > + * get_cpu_iowait_time_us() > > + * > > + * 2. synchronization with other hw blocks > > + * > > + * > > + */ > > + > > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > + > > +#include <linux/module.h> > > +#include <linux/kernel.h> > > +#include <linux/delay.h> > > +#include <linux/kthread.h> > > +#include <linux/freezer.h> > > +#include <linux/cpu.h> > > +#include <linux/thermal.h> > > +#include <linux/slab.h> > > +#include <linux/tick.h> > > +#include <linux/debugfs.h> > > +#include <linux/seq_file.h> > > +#include <linux/nmi.h> > > + > drivers/thermal/intel_powerclamp.c: In function ‘clamp_thread’: > drivers/thermal/intel_powerclamp.c:435:4: error: implicit declaration of > function ‘local_touch_nmi’ [-Werror=implicit-function-declaration] > > changing to > #include <asm/nmi.h> > fixes the problem. > and this is because I have neither CONFIG_HAVE_NMI_WATCHDOG set nor CONFIG_HARDLOCKUP_DETECTOR set in my configuration. :) thanks, rui -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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