On Fri, 2011-11-04 at 14:06 +0530, Suzuki Poulose wrote: > On 11/03/11 05:06, Josh Poimboeuf wrote: > > On Tue, 2011-10-25 at 17:23 +0530, Suzuki K. Poulose wrote: > > @@ -137,6 +137,9 @@ get_type: > > lwz r0, 8(r9) /* r_addend */ > > add r0, r0, r3 /* final addend */ > > stwx r0, r4, r7 /* memory[r4+r7]) = (u32)r0 */ > > + dcbst r4,r7 /* flush dcache line to memory */ > > + sync /* wait for flush to complete */ > > + icbi r4,r7 /* invalidate icache line */ > > Doing it this way has two drawbacks : > > 1) Placing it here in relocate would do the flushing for each and every > update.
I agree. My kernel had around 80,000 relocations, which means 80,000 d-cache line flushes (for a 32k d-cache) and 80,000 i-cache line invalidates (for a 32k i-cache). Which is obviously a little overkill. Although I didn't notice a performance hit during boot. > 2) I would like to keep this code as generic as possible for the PPC32 code. > > Could we move this to the place from relocate is called and flush the d-cache > and > i-cache entirely ? Why not put the cache flushing code at the end of relocate? Would some of the other PPC32 platforms not require the cache flushing? My PPC32 knowledge is 4xx-centric, so please feel free to rewrite the patch as needed to accommodate other PPC32 cores. Thanks, Josh _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
