[meta-ti] poor performance of OpenEmbedded on, BeagleBoneBlack compared to Debian

[Robert Nelson]

On Thu, Sep 4, 2014 at 10:48 AM, Denys Dmytriyenko <denys at ti.com> wrote:
> On Thu, Sep 04, 2014 at 10:37:24AM -0500, Peter A. Bigot wrote:
>> On 09/04/2014 10:00 AM, Denys Dmytriyenko wrote:
>> >On Thu, Sep 04, 2014 at 02:50:03PM +0000, Mikhail Zakharov wrote:
>> >>On Wed, Sep 3, 2014 at 8:59 PM, Peter A. Bigot <pab at pabigot.com> wrote:
>> >>
>> >>>One anomaly I've found is the CPU frequency range.  On debian we have:
>> >>>
>> >>>    debian at beaglebone:~$ cat
>> >>>/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
>> >>>    300000 600000 800000 1000000
>> >>>
>> >>>while on OE we have:
>> >>>
>> >>>    root at beaglebone:~# cat
>> >>>/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
>> >>>    300000 600000 720000 800000
>> >>Stock yocto-bsp is missing a few things that can be found in Robert
>> >>Nelson's patchset for 3.14 linux kernel.
>> >>
>> >>There are lots of other functionality that is missing from yocto-bsp
>> >>kernel for Beaglebone. I suggest you take at the following repos and
>> >>scavenge for what you need :P
>> >First of all, this is meta-ti mailing list for the corresponding BSP. That's
>> >what Peter was asking for, comparing to Robert's Debian and Yocto reference
>> >BSPs, not the other way around.
>> >
>> >Second, Yocto reference BSP is that way for a reason - it's a reference BSP
>> >done with pure mainline kernel and u-boot components w/o any patching on top.
>> >That's its entire purpose. For anything else special, including performance
>> >tweaks, there are other BSPs available. If there is an issue with performance
>> >in meta-ti, we'll investigate it and try to match with Robert's BSP.
>>
>> Yes, at this time meta-ti's BSP performs as well as I've seen any
>> OE-based system, and gets several things right that meta-yocto-bsp
>> does not (and one thing wrong that meta-yocto-bsp gets right, I
>> think; still investigating, will follow-up when I'm sure).
>>
>> I've also verified that performance with a native gcc 4.9.1 build on
>> BeagleBone with hard float is poor, so it's not due to the way OE
>> builds gcc.  I have several competing hypotheses to test.
>
> Can you please point to the test case you were using to measure time? I'd like
> to try it with few different toolchains here as well. BTW, we are currently
> using Linaro gcc-4.7.3 - I'm wondering how it performs.
>
>
>> But I'm still looking for a way to set the CPU frequency to the
>> higher values supported on Beaglebone Black.  I had hoped meta-ti's
>> would be able to do that, since it has bone vs boneblack device
>> trees and u-boot detection.
>>
>> Any hints where to look for clock settings?
>
> Some of those values are considered overclocking and according to the manual
> will reduce the lifespan of the part...

That's an odd statement, as the parts used on the beaglebone black are
binned and sold for 1Ghz operation.

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/