0.22.0's first launch on the tablet: QNN could not create its device
(QNN_DEVICE_ERROR_INVALID_CONFIG), the session built anyway with every
node on the CPU behind the provider, and the probe timed that - 28.5 ms
against the CPU's own 19.4 - and rejected the Hexagon. The verdict was
cached under the fingerprint, so every model stayed on the CPU on every
later launch: AI denoise took 30-131 s a photograph instead of seconds.
The same A16W8 detector with the APK's own libraries runs on the HTP in
4.4 ms.
The probe's Hexagon session now sets session.disable_cpu_ep_fallback, so
a device that cannot take the graph fails the probe instead of being timed
as the CPU. Only the probe: shipped graphs may keep nodes on the CPU on
purpose. And a selection that fell back to the CPU after an accelerator
failed or lost is probed again on the next launches, up to three probes
per fingerprint; a cache written by 0.22.0 reads as never retried, so the
tablet probes again once this is installed.
dtourolle
f20e481358