[RFC] Efficiency of the phandle_cache on ppc64/SLOF

[Sebastian Andrzej Siewior]

On 2019-11-29 20:14:47 [-0600], Frank Rowand wrote:
> The hash used is based on the assumptions you noted, and as stated in the
> code, that phandle property values are in a contiguous range of 1..n
> (not starting from zero), which is what dtc generates.
> 
> We knew that for systems that do not match the assumptions that the hash
> will not be optimal.  Unless there is a serious performance problem for
> such systems, I do not want to make the phandle hash code more complicated
> to optimize for these cases.  And the pseries have been performing ok
> without phandle related performance issues that I remember hearing since
> before the cache was added, which could have only helped the performance.
> Yes, if your observations are correct, some memory is being wasted, but
> a 64 entry cache is not very large on a pseries.

okay, so it is nothing new and everyone is aware of the situation. I
move on then :)

> -Frank

Sebastian