Hi,
First of all, when T/O performance is concerned, we only consider surface temperature. To the best of my knowledge, there is no legislation on performance penalty whenever there an inverson layer and it's not explicitly identified by our briefing package.
However, I do brief for it when conditions suggest an inversion layer is in the region, namely high QNH, a distinct layer of smog/ chimmney smoke flattening out. Should there be a loss of power/speed, I will have go on MAX power and watch out for cleaning up the A/C while on a turn as well.
Cheers,
lion-g