linux-kernel - Re: [patch 2/2] x86: Manage ENERGY_PERF_BIAS based on cpufreq governor

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Message-ID: <20100304232756.GA13895@redhat.com>
Date:	Thu, 4 Mar 2010 18:27:56 -0500
From:	Dave Jones <davej@...hat.com>
To:	venkatesh.pallipadi@...el.com
Cc:	Ingo Molnar <mingo@...e.hu>, H Peter Anvin <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Len Brown <lenb@...nel.org>, linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	Venkatesh Pallipadi <venkatesh.pallipadi@...il.com>
Subject: Re: [patch 2/2] x86: Manage ENERGY_PERF_BIAS based on cpufreq
 governor - v2

On Thu, Mar 04, 2010 at 03:14:56PM -0800, Venki Pallipadi wrote:
 
 > +	if (!strncmp(gov->name, "performance", strlen("performance")))
 > +		epb_val = ENERGY_PERF_BIAS_PERF;
 > +	else if (!strncmp(gov->name, "powersave", strlen("powersave")))
 > +		epb_val = ENERGY_PERF_BIAS_POWER;
 > +	else
 > +		epb_val = ENERGY_PERF_BIAS_ONDEMAND;
 > +
 > +	set_epb_on_cpu(epb_val, cpu);
 > +	return 0;

hardcoding a list of cpufreq governors is kinda icky, but I don't have
a better solution.  We'll just have to be mindful of it if we ever
get around to finally making performance/powersave personalities
of ondemand as was discussed years ago.

What if the governor is set to 'userspace' ?
powernowd/cpufreqd are sort of ondemand-done-in-userspace, but there
may also be other userspace governors we don't know about.
I suppose it's not catastrophic..

	Dave

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