linux-kernel - Re: PATCH] ftrace: Add a C/P state tracer to help power optimization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20081028100403.GC15734@elte.hu>
Date:	Tue, 28 Oct 2008 11:04:03 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	"Frank Ch. Eigler" <fche@...hat.com>, linux-kernel@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>, lenb@...nel.org
Subject: Re: PATCH] ftrace: Add a C/P state tracer to help power
	optimization


* Arjan van de Ven <arjan@...radead.org> wrote:

> On Mon, 27 Oct 2008 15:47:30 -0400
> fche@...hat.com (Frank Ch. Eigler) wrote:
> 
> > 
> > Arjan van de Ven <arjan@...radead.org> writes:
> > 
> > > [...]
> > > --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> > > +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
> > > [...]
> > > @@ -427,6 +429,8 @@ static int acpi_cpufreq_target(struct
> > > cpufreq_policy *policy, }
> > >  	}
> > >  
> > > +	trace_power_mark(&it, POWER_PSTATE, next_perf_state);
> > > +
> > >  	switch (data->cpu_feature) {
> > >  	case SYSTEM_INTEL_MSR_CAPABLE:
> > >  		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
> > > [...]
> > 
> > Is there some reason that this doesn't use tracepoints instead
> > of such a single-backend hook?
> 
> because it's a ton simpler this way? do simple things simpe and all 
> that....

correct.

	Ingo
--
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/