Raspberry Pi2 performance

Alexander Stein alexanders83 at web.de
Fri Jul 24 01:10:25 PDT 2015


after getting dcache support for Raspberry Pi 1 (see other thread) to work: I wanted to do that for rpi2 too.
But even without dcaches rpi2 is slower than rpi1 for both MMC and USB ethernet.
I have no idea why, but trying the new dhry command from current origin/master confirms my suspicion.

bcm2835 (w/o dcache):
U-Boot> dhry 
1000000 iterations in 10948 ms: 91340/s, 51 DMIPS

bcm2835 (w/ dcache):
U-Boot> dhry 
1000000 iterations in 1656 ms: 603864/s, 343 DMIPS

bcm2836 (w/o dcache):
U-Boot> dhry 
1000000 iterations in 43247 ms: 23122/s, 13 DMIPS

Independent from the dcache difference it seems totally wrong to me that the bcm2836 is about 4 times slower than the bcm2835. 
I have this in my config.txt of bcm2835:
> kernel=u-boot.bin
> #force rpi to assume there is always a HDMI link
> hdmi_force_hotplug=1
> #force normal HDMI (incl. sound)
> hdmi_drive=2
> gpu_mem=16
> arm_freq=800
> core_freq=300
> sdram_freq=400
> over_voltage=0

While having only this line at bcm2836:
> kernel=u-boot.bin

Does someone experience the same? What might be wrong here? Do I need some config.txt settings to get bcm2836 running as fast as it should.

Best regards,

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