On Sat, 22 Sep 2012, Gabriel Paubert wrote: > On Sat, Sep 22, 2012 at 02:12:42PM +0400, malc wrote: > > On Sat, 22 Sep 2012, Segher Boessenkool wrote: > > > > > > Is it possible to determine if _native_ isel is available from userspace > > > > somehow? > > > > > > Just try to execute one and catch the SIGILL? > > > > > > > Unfortunately my kernel emulates ISEL for me in this case, so i don't > > get any SIGILLs. > > Perform a few isels in a loop between a couple of mftb and measure the > shortest time it takes. Any emulation will take tens of timebase ticks, > hardware implementation will return very small values, perhaps even > 0 depending on the relationship between core and timebase frequencies. > > I don't remember whether it's necessary inserting an isync between the > two mftb. I believe that even on the most OOO machines, two mftb in > a row will not be reordered to the point that the second executes before > the first. >
Thanks for suggestion, but i'd rather not play with heuristics. -- mailto:av1...@comtv.ru _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
