Hi Anton, On Wed, Aug 05, 2015 at 02:03:00PM +1000, Anton Blanchard wrote: > While looking at traces of kernel workloads, I noticed places where gcc > used a large number of non volatiles. Some of these functions > did very little work, and we spent most of our time saving the > non volatiles to the stack and reading them back.
That is something that should be fixed in GCC -- do you have an example of such a function? > It made me wonder if we have the right ratio of volatile to non > volatile GPRs. Since the kernel is completely self contained, we could > potentially change that ratio. > > Attached is a quick hack to gcc and the kernel to decrease the number > of non volatile GPRs to 8. I'm not sure if this is a good idea (and if > the volatile to non volatile ratio is right), but this gives us > something to play with. Instead of the GCC hack you can add a bunch of -fcall-used-r14 etc. options; does that not work for you? Segher _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
