Re: [PATCH] powerpc/64s/radix: Don't prefetch DAR in update_mmu_cache

2020-06-09 Thread Michael Ellerman
On Mon, 4 May 2020 22:29:07 +1000, Nicholas Piggin wrote: > The idea behind this prefetch was to kick off a page table walk before > returning from the fault, getting some pipelining advantage. > > But this never showed up any noticable performance advantage, and in > fact with KUAP the

[PATCH] powerpc/64s/radix: Don't prefetch DAR in update_mmu_cache

2020-05-04 Thread Nicholas Piggin
The idea behind this prefetch was to kick off a page table walk before returning from the fault, getting some pipelining advantage. But this never showed up any noticable performance advantage, and in fact with KUAP the prefetches are actually blocked and cause some kind of micro-architectural