On Sat, 2 Apr 2016, Andy Lutomirski wrote: > On Fri, Apr 1, 2016 at 9:10 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > >> + if (turbo_mode) > >> + write_cr0(cr0 & ~X86_CR0_CD); > >> + else > >> + write_cr0(cr0 | X86_CR0_CD); > > > > I think proper turbo mode disable requires ~(X86_CR0_CD | X86_CR0_NW) > > I thought that made no difference on family 6 and P4 and was actively > dangerous (disabled coherency) before. At least, that's what the > table of caching modes and the footnote seems to say. CD=0 and NW=1 result in #GP, which might be your intent as that is definitely the slowest mode you can achieve. But you should add a comment at least. > I think we should merge this patch and add a special-case so that > calling unlink on turbo_mode sets it to zero. Then people who rm -rf > / will brick their systems more slowly :) While at it can you please make a turbo = 0 call when we hit a WARN/BUG/Panic so the messages spill slower over the screen? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
