Re: [RFC PATCH v2 0/4] CPUs capacity information for heterogeneous systems

Juri Lelli
2016-01-19T14:29:17Z

On 19/01/16 11:23, Juri Lelli wrote:
> Hi Catalin,
>
> On 19/01/16 10:59, Catalin Marinas wrote:
> > On Mon, Jan 18, 2016 at 05:42:58PM +0100, Vincent Guittot wrote:
> > > On 18 January 2016 at 17:30, Juri Lelli <juri.lelli@arm.com> wrote:
> > > > On 18/01/16 17:13, Vincent Guittot wrote:
> > > >> On 18 January 2016 at 16:13, Juri Lelli <juri.lelli@arm.com> wrote:
> > > >> > On 15/01/16 11:50, Steve Muckle wrote:
> > > >> >> On 01/08/2016 06:09 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).

Best,

- Juri