ubuntu-phone team mailing list archive

[Michi Henning <michi.henning@xxxxxxxxxxxxx>]

> I wouldn't make the assumption that confined processes are necessarily running in the phone as i believe the convergence plan is to have confined apps on the desktop.
> 
Right.
> Aside from that, i would just try to do whatever it is you're trying to do and then catch the failure as gracefully as possible when it fails on the phone, if you can. Better to ask forgiveness than permission ;-)
> 
No can do, I’m afraid. The decision as to how many concurrent extractions to allow fundamentally depends on knowing whether or not we are using the Android hardware codecs. There is no way to figure this out that I know of, other than to ask “am I running on touch?” because, by definition, we *know* (at least for the time being) that, on touch, we are using hardware codecs.

I cannot catch the failure. For one, it is non-deterministic. Secondly, when the failure does happen, it manifests itself as several unkillable processes that are stuck in the kernel, each spinning at 100% CPU for 30 seconds. That failure mode is not only rather hard to detect, it’s also not a good way to find out that I shouldn’t have done what I did…

Right now, we are working around the problem by disabling concurrent extraction whenever we are running on Arm. But that disables concurrency even when software codecs are in use, such as on a Chromebook. In turn, that means we are not using three perfectly good CPUs that we could use, if only we had an answer to the question :-(

Michi.