[Liverpool] RaspPi talk

[Sebastian Arcus]

On 05/03/15 08:37, jn1057 wrote:
> Hi! Although i didn't quite understand all of it i got the gist! Yes that issue was discussed. V1 r.pis are  essentially limited by the cpu with plenty of capacity available and unusable at the I/o interfaces. V2 r.pis have a better balance of on board resources for ultimate performance if/when they are used as a model cloud.
>
> All slides and other related info from the doctor are available at Www.poscotso.info
Thanks for that. Looking at the various specs online, it seems that the 
Pi2 has the lan attached to the usb bus as well. In that case, 
technically the CPU is not truly the limiting factor - it is just being 
hogged down by having to service inefficient usb attached interfaces (OK 
- maybe the correct phrasing would be "less efficient" interfaces then 
for example SATA or PCI-e). I guess a lot of the stats last night, 
specially when it came to Pi vs. Intel i5, could have been predicted by 
in large based on the fact that the Pi architecture doesn't have a PCI-e 
or SATA bus. Both would allow the storage and network side of things to 
function at much higher performance with much lower CPU usage.

Still, they seem to have done fantastic work in porting Docker and some 
of the other virtualisation bits to the Pi. Good work!


>
> Regards
>
> Sebastian Arcus <s.arcus at open-t.co.uk> wrote:
>
>> I found the talk last night really interesting. I didn't catch all of it
>> - I wonder if anybody raised the issue that the first generation of Pi
>> has the ethernet on the USB bus - which I guess would add a lot of CPU
>> overhead in processing network traffic (interrupts etc.) I know there
>> was a lot of moaning on the forums that the particular arrangement above
>> leads to really poor network performance. I'm not really sure what's the
>> situation with the second generation Pi in that respect.
>>
>> Sorry I couldn't stay until the end. It was good seeing you all though -
> >from the back :-)
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