[Stephen Beckwith]

Neeraj;

Thank you for your feedback.  The DK2 system has a few other applications loaded, but “pidstat” shows they are not running or consuming fractional percentage of CPU time.  I will will be doing a “deep dive” next week on the data I’ve collected using “sysstat” utilities.  Thanks for the pointer on the clocks, I will take a closer look-see.

Thank You.

 

Regards,

Stephen Beckwith

[Stephen Beckwith]

Neeraj;

Thank  you for  your reply.  That’s what I was looking for.  So the OSD32 uses the same x16 interface as the STM32MP-DK2.  Combined with the information from Aedan on the latency, the situation now gets “stickier”. . . .

Per your comment Aedan:

– We are not seeing a performance decrease, rather we are seeing a performance increase on the OSD32 which is clocked ~ 20% slower than the DK2.  I was able to “force” the DK2 to run at 800MHz (verified by checking:  /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_curr_freq.  Initial testing revealed that the DK2 was throttling between 400 and 800 MHz, where the OSD seems to be “fixed” at 650MHz

cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq

650000

For the same test conditions on both platforms we are seeing:

DK2 Kit:  Median CPU load:  20.9800%

OSD32:  Median CPU load:  18.7000%

This is based upon a 30 minute capture of sysstat data.  It goes against “logic” that a system that is clocked ~ 20% slower would actually show a increase in performance.  (less load).  I would have expected the OSD32 to be ~ 25% when you “do the math”.   A slower CPU clock would mean things take longer and would put more “pressure” on the system, not less.

A x32 memory interface with better timing might be a good explanation for this, however, if you are saying that the OSD has the same x16 interface, then I’m somewhat beside myself as to why this is the case.

Given that the OSD is “all inside” the chip, and doesn’t have to deal with DDR->Phy->bondout->pin->PCB->DDR pin->DDR Device path, I would think you “could” run this interface quicker.  Also, why not use a x32 interface.

Any thoughts?  Any suggestions as to where to look for differences?

Thank you for your speedy reply.

 

Regards,

Stephen Beckwith

 

 

 

[Author]

Posts