On Nov 21, 2007, at 3:12 AM, Benjamin Herrenschmidt wrote: > > On Tue, 2007-11-20 at 15:01 -0600, Kumar Gala wrote: >>> Given that the instruction is meant to be a performance enhancement, >>> we should probably warn the first few times it's emulated, so the >> user >>> knows they should change their toolchain setup if possible. >> >> The same is true of mcrxr, popcntb, and possibly string ld/st. >> >> Feel free to submit a patch that warns about their usage. > > At least we should keep counters... best would be per-task counters > in /proc but that sounds harder :-) > > I remember in the early days of powerpc, it wasn't uncommon to have > apps > with issues because they used 601 only bits on 603/4 that had to be > emulated (such as old POWER opcodes). On MacOS, we used to have a > system-wide counter of the number of emulated instructions we could > use > to detect these things.
I think having some form of per insn group counters would be useful as well. I know it would be helpful to debug user problems if they are doing a lot of FP emu or the like and don't know it. - k _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
