On Thu, Jul 7, 2011 at 10:21 PM, David Miller <davem@xxxxxxxxxxxxx> wrote: > From: Christoph Lameter <cl@xxxxxxxxx> > Date: Thu, 7 Jul 2011 14:12:37 -0500 (CDT) > >> On Thu, 7 Jul 2011, Pekka Enberg wrote: >> >>> On Thu, 7 Jul 2011, Pekka Enberg wrote: >>> > > Looks good to me. Christoph, David, ? >>> >>> On Thu, 2011-07-07 at 13:17 -0500, Christoph Lameter wrote: >>> > The reason debug code is there is because it is useless overhead typically >>> > not needed. There is no point in optimizing the code that is not run in >>> > production environments unless there are gross performance issues that >>> > make debugging difficult. A performance patch for debugging would have to >>> > cause significant performance improvements. This patch does not do that >>> > nor was there such an issue to be addressed in the first place. >>> >>> Is there something technically wrong with the patch? Quoting the patch >>> email: >>> >>> (Compiling some project with different options) >>> make -j12 make clean >>> slub_debug disabled: 1m 27s 1.2 s >>> slub_debug enabled: 1m 46s 7.6 s >>> slub_debug enabled + this patch: 1m 33s 3.2 s >>> >>> check_bytes still shows up high, but not always at the top. >>> >>> That's significant enough speedup for me! >> >> Ok. I had a different set of numbers in mind from earlier posts. >> >> The benefit here comes from accessing memory in larger (word) chunks >> instead of byte wise. This is a form of memscan() with inverse matching. >> >> Isnt there an asm optimized version that can do this much better (there is >> one for memscan())? Optimizing this in core code by codeing something as >> generic as that is not that good since the arch code can deliver better >> performance and it seems that this is functionality that could be useful >> elsewhere. > > You're being so unreasonable, just let the optimization in, refine it > with follow-on patches. I applied the patch. I think a follow up patch that moves the function to lib/string.c with proper generic name would be in order. Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href