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. -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>