Hi Jiri, 2014-04-28 (월), 11:48 +0200, Jiri Olsa: > On Sun, Apr 27, 2014 at 11:29:21PM +0900, Namhyung Kim wrote: > > Hi Jiri, > > > > 2014-04-17 (목), 19:39 +0200, Jiri Olsa: > > > Caching registers value into an array. Got about 4% speed up > > > of perf_reg_value function for report command processing > > > dwarf unwind stacks. > > > > I'm not familiar with the code base, so probably silly questions: Where > > does the speed up come from? IOW I don't know what's the difference > > between the regs->regs and regs->cached_regs. And does the cached_regs > > contain correct values of registers for each frame? > > the current way register's value is accessed is to get its > index in the sample's regs array.. based on register's id > and the registers mask > > so each time you want register value you traverse the registers > mask and count reg's index for the sample regs array > > this patch does this only once for each register (at the time it's > first accessed) and cache its value in the array (cache_regs). The > cache_mask is used to identify which regs are already cached.
That means it'll get the same value everytime it accesses a register in frames in a sample? Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
