From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Nicolas Pitre <nicolas.pitre@linaro.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Preeti U Murthy <preeti@linux.vnet.ibm.com>,
Len Brown <len.brown@intel.com>,
Preeti Murthy <preeti.lkml@gmail.com>,
"mingo@redhat.com" <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
LKML <linux-kernel@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Lists linaro-kernel <linaro-kernel@lists.linaro.org>
Subject: Re: [RFC PATCH 3/3] idle: store the idle state index in the struct rq
Date: Tue, 4 Feb 2014 10:14:05 +0100 [thread overview]
Message-ID: <20140204091405.GB19156@gmail.com> (raw)
In-Reply-To: <20140203145605.GL8874@twins.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
> [...]
>
> The reason Ingo took it out was that these measured numbers would
> slightly vary from boot to boot making it hard to compare
> performance numbers across boots.
>
> There's something to be said for either case I suppose.
Yeah, so we could put the parameters back by measuring it in
user-space via a nice utility in tools/, and by matching it to
relevant hardware signatures (CPU type and cache sizes), plus doing
some defaults for when we don't have any signature... possibly based
on a fuzzy search to find the 'closest' system in the table of
constants.
That would stabilize the boot-to-boot figures while still keeping most
of the system specific-ness, in a maintainable fashion.
The downside is that we'd have to continuously maintain a table of all
this info, with new entries added when new CPUs are introduced on the
market. That's an upside too, btw.
Thanks,
Ingo
next prev parent reply other threads:[~2014-02-04 9:14 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 14:09 [RFC PATCH 0/3] cpuidle/sched: move main idle function in the idle.c Daniel Lezcano
2014-01-30 14:09 ` [RFC PATCH 1/3] cpuidle: split cpuidle_idle_call main function into functions Daniel Lezcano
2014-01-30 15:27 ` Peter Zijlstra
2014-01-30 15:39 ` Daniel Lezcano
2014-01-30 19:39 ` Nicolas Pitre
2014-01-31 14:10 ` Daniel Lezcano
2014-01-30 14:09 ` [RFC PATCH 2/3] cpuidle: move the cpuidle_idle_call function to idle.c Daniel Lezcano
2014-01-30 19:42 ` Nicolas Pitre
2014-01-30 14:09 ` [RFC PATCH 3/3] idle: store the idle state index in the struct rq Daniel Lezcano
2014-01-30 15:31 ` Peter Zijlstra
2014-01-30 16:27 ` Daniel Lezcano
2014-01-30 16:35 ` Peter Zijlstra
2014-01-30 17:25 ` Daniel Lezcano
2014-01-30 17:50 ` Lorenzo Pieralisi
2014-01-30 21:02 ` Nicolas Pitre
2014-01-31 9:46 ` Vincent Guittot
2014-01-31 10:04 ` Lorenzo Pieralisi
2014-01-31 10:44 ` Daniel Lezcano
2014-01-31 8:45 ` Preeti Murthy
2014-01-31 9:02 ` Peter Zijlstra
2014-01-31 9:39 ` Preeti U Murthy
2014-01-31 10:24 ` Peter Zijlstra
2014-01-31 14:04 ` Daniel Lezcano
2014-01-31 14:12 ` Dietmar Eggemann
2014-01-31 15:07 ` Arjan van de Ven
2014-01-31 15:37 ` Daniel Lezcano
2014-01-31 15:50 ` Arjan van de Ven
2014-01-31 16:35 ` Daniel Lezcano
2014-01-31 16:42 ` Arjan van de Ven
2014-01-31 18:19 ` Nicolas Pitre
2014-02-01 6:00 ` Brown, Len
2014-02-01 15:31 ` Nicolas Pitre
2014-02-01 19:39 ` Brown, Len
2014-02-01 20:13 ` Nicolas Pitre
2014-02-01 15:40 ` Lorenzo Pieralisi
2014-02-03 12:54 ` Morten Rasmussen
2014-02-03 14:38 ` Arjan van de Ven
2014-02-03 14:56 ` Peter Zijlstra
2014-02-03 16:17 ` Arjan van de Ven
2014-02-11 16:41 ` Peter Zijlstra
2014-02-11 17:12 ` Arjan van de Ven
2014-02-11 19:47 ` Peter Zijlstra
2014-02-12 15:16 ` Lorenzo Pieralisi
2014-02-12 16:14 ` Arjan van de Ven
2014-02-12 17:37 ` Lorenzo Pieralisi
2014-02-12 19:05 ` Nicolas Pitre
2014-02-04 9:14 ` Ingo Molnar [this message]
2014-02-04 14:53 ` Arjan van de Ven
2014-02-04 14:56 ` Arjan van de Ven
2014-02-03 14:58 ` Nicolas Pitre
2014-01-31 10:15 ` Daniel Lezcano
2014-02-03 6:33 ` Preeti U Murthy
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