Le 15/03/2015 04:11, Simon Wise a écrit :

 Apparently there is some support beyond Es, but not enough to run gem and as 
not at all documented.
i was to much optimistic and did not double check the informations i found 
announcing openGL support.
thanks for the clarification.
cheers
c



If you are experimenting with an RPi 2 then with audio the load balancing by 
switching cores will add considerable latency (X-runs at latencies the RPi 1 
handles fine). This is probably due to cache invalidation on a core switch, and 
the time required to fetch everything again if the switch occurs at an 
inopportune moment re buffers and deadlines. For low latency audio you will 
need to use linux cpu affinity to always put the main pd process on a specific 
core, this can also be achieved by the no-sleep flag in pd which sets pd to use 
busy-waiting (I believe) so run continuously and fully occupy one core. There 
may be advantages to either technique, no point sleeping a process if it owns 
the core exclusively, but running 100% may also lead to heating issues and a 
need to run at lower clock speeds... depending I guess on how the no-sleep is 
implemented.

This could prove useful if you are ready to manually split your processing 
between separate pd patches and script the launching to achieve the cpu 
affinity required. cpusets could help more, making a core (or three) dedicated 
exclusively to a pd process each while the remaining core(s) run anything else.

Some have said there may be heating issues without load balancing, but the 
devices are cheap so a shortened life probably isn't an issue, other heat 
problems could arise ... maybe slow down the clock speed or add a decent heat 
sink to the chip if you are playing with this option.

Simon


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