From: Steve Muckle <steve.muckle@linaro.org>
To: Juri Lelli <juri.lelli@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Mark Rutland <mark.rutland@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Mark Brown <broonie@kernel.org>,
Will Deacon <will.deacon@arm.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
LAK <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH v2 0/4] CPUs capacity information for heterogeneous systems
Date: Tue, 19 Jan 2016 11:48:15 -0800 [thread overview]
Message-ID: <569E92FF.4000006@linaro.org> (raw)
In-Reply-To: <20160119142933.GF8573@e106622-lin>
On 01/19/2016 06:29 AM, Juri Lelli wrote:
>>> Two questions:
>>> > >
>>> > > 1. How is the boot time affected by the benchmark?
>>> > > 2. How is the boot time affected by considering all the CPUs the same?
>>> > >
>>> > > My preference is for DT and sysfs (especially useful for
>>> > > development/tuning) but I'm not opposed to a boot-time benchmark if
>>> > > people insist on it. If the answer to point 2 is "insignificant", we
>>> > > could as well defer the capacity setting to user space (sysfs).
>>> > >
>> >
>> > Given that we are not targeting boot time with this, but rather better
>> > performance afterwards, I don't expect significant differences; but,
>> > I'll get numbers :).
>> >
> I've got some boot time numbers on TC2 and Juno based on timestamps.
> They are of course not accurate and maybe not so representative of
> products, but I guess still ballpark right.
>
> I'm generally seeing ~1sec increase in boot time for 1 and practically
> no difference for 2 (even after having added patches that provide
> runtime performance improvements).
One second is considerable IMO. Aside from the general desire to have
shorter boot times on any platform there are environments like
automotive where boot time is critical.
How are the CPUs numbered on TC2 and Juno? When all CPUs are considered
the same, is work running on the big CPUs because of the way they are
numbered?
thanks,
Steve
WARNING: multiple messages have this Message-ID (diff)
From: steve.muckle@linaro.org (Steve Muckle)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v2 0/4] CPUs capacity information for heterogeneous systems
Date: Tue, 19 Jan 2016 11:48:15 -0800 [thread overview]
Message-ID: <569E92FF.4000006@linaro.org> (raw)
In-Reply-To: <20160119142933.GF8573@e106622-lin>
On 01/19/2016 06:29 AM, Juri Lelli wrote:
>>> Two questions:
>>> > >
>>> > > 1. How is the boot time affected by the benchmark?
>>> > > 2. How is the boot time affected by considering all the CPUs the same?
>>> > >
>>> > > My preference is for DT and sysfs (especially useful for
>>> > > development/tuning) but I'm not opposed to a boot-time benchmark if
>>> > > people insist on it. If the answer to point 2 is "insignificant", we
>>> > > could as well defer the capacity setting to user space (sysfs).
>>> > >
>> >
>> > Given that we are not targeting boot time with this, but rather better
>> > performance afterwards, I don't expect significant differences; but,
>> > I'll get numbers :).
>> >
> I've got some boot time numbers on TC2 and Juno based on timestamps.
> They are of course not accurate and maybe not so representative of
> products, but I guess still ballpark right.
>
> I'm generally seeing ~1sec increase in boot time for 1 and practically
> no difference for 2 (even after having added patches that provide
> runtime performance improvements).
One second is considerable IMO. Aside from the general desire to have
shorter boot times on any platform there are environments like
automotive where boot time is critical.
How are the CPUs numbered on TC2 and Juno? When all CPUs are considered
the same, is work running on the big CPUs because of the way they are
numbered?
thanks,
Steve
next prev parent reply other threads:[~2016-01-19 19:48 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-08 14:09 [RFC PATCH v2 0/4] CPUs capacity information for heterogeneous systems Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-08 14:09 ` [RFC PATCH v2 1/4] ARM: initialize cpu_scale to its default Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-08 14:09 ` [RFC PATCH v2 2/4] drivers/cpufreq: implement init_cpu_capacity_default() Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-08 14:09 ` [RFC PATCH v2 3/4] arm: Enable dynamic CPU capacity initialization Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-08 14:09 ` [RFC PATCH v2 4/4] arm64: " Juri Lelli
2016-01-08 14:09 ` Juri Lelli
2016-01-15 18:01 ` [RFC PATCH v2 0/4] CPUs capacity information for heterogeneous systems Mark Brown
2016-01-15 18:01 ` Mark Brown
2016-01-18 15:01 ` Juri Lelli
2016-01-18 15:01 ` Juri Lelli
2016-01-15 19:50 ` Steve Muckle
2016-01-15 19:50 ` Steve Muckle
2016-01-18 15:13 ` Juri Lelli
2016-01-18 15:13 ` Juri Lelli
2016-01-18 16:13 ` Vincent Guittot
2016-01-18 16:13 ` Vincent Guittot
2016-01-18 16:30 ` Juri Lelli
2016-01-18 16:30 ` Juri Lelli
2016-01-18 16:42 ` Vincent Guittot
2016-01-18 16:42 ` Vincent Guittot
2016-01-18 17:08 ` Juri Lelli
2016-01-18 17:08 ` Juri Lelli
2016-01-18 17:23 ` Vincent Guittot
2016-01-18 17:23 ` Vincent Guittot
2016-01-19 10:59 ` Catalin Marinas
2016-01-19 10:59 ` Catalin Marinas
2016-01-19 11:23 ` Juri Lelli
2016-01-19 11:23 ` Juri Lelli
2016-01-19 14:29 ` Juri Lelli
2016-01-19 14:29 ` Juri Lelli
2016-01-19 19:48 ` Steve Muckle [this message]
2016-01-19 19:48 ` Steve Muckle
2016-01-19 21:10 ` Mark Brown
2016-01-19 21:10 ` Mark Brown
2016-01-20 10:22 ` Juri Lelli
2016-01-20 10:22 ` Juri Lelli
2016-01-18 19:25 ` Steve Muckle
2016-01-18 19:25 ` Steve Muckle
2016-01-19 15:05 ` Peter Zijlstra
2016-01-19 15:05 ` Peter Zijlstra
2016-01-19 17:50 ` Mark Brown
2016-01-19 17:50 ` Mark Brown
2016-01-20 10:25 ` Juri Lelli
2016-01-20 10:25 ` Juri Lelli
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