1. arale performance is quite poor, and we've known this for a long time. I mean the device itself. Its frequency governor keeps clock speeds so low for so long what frame rates rarely appear smooth (see bug 1488386). This is however a bug in the arale kernel drivers and not a bug in Mir or Unity8 that we can easily work around.
2. Are you sure 20-30% counts as high or a bug on this particular device? CPU usage varies wildly between graphics drivers and sometimes high CPU for constantly rendering is unavoidable. A good example is desktop -- you will find the Intel graphics driver uses very little CPU whereas Nvidia will use large amounts of CPU. Whether this is a bug or a feature that allows the driver to improve performance internally is not a question we can easily answer.
I'm not sure this is a Mir bug at all, or something we can improve in the above components at least.
Two things worth noting:
1. arale performance is quite poor, and we've known this for a long time. I mean the device itself. Its frequency governor keeps clock speeds so low for so long what frame rates rarely appear smooth (see bug 1488386). This is however a bug in the arale kernel drivers and not a bug in Mir or Unity8 that we can easily work around.
2. Are you sure 20-30% counts as high or a bug on this particular device? CPU usage varies wildly between graphics drivers and sometimes high CPU for constantly rendering is unavoidable. A good example is desktop -- you will find the Intel graphics driver uses very little CPU whereas Nvidia will use large amounts of CPU. Whether this is a bug or a feature that allows the driver to improve performance internally is not a question we can easily answer.
I'm not sure this is a Mir bug at all, or something we can improve in the above components at least.