On Sat, Jun 30, 2012 at 4:01 AM, Nai Xia <nai.xia@xxxxxxxxx> wrote: > On Sat, Jun 30, 2012 at 2:53 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote: >> On Fri, 2012-06-29 at 12:51 -0400, Dor Laor wrote: >>> The previous comments were not shouts but the mother of all NAKs. >> >> I never said any such thing. I just said why should I bother reading >> your stuff if you're ignoring most my feedback anyway. >> >> If you want to read that as a NAK, not my problem. > > Hey guys, Can I say NAK to these patches ? > > Now I aware that this sampling algorithm is completely broken, if we take > a few seconds to see what it is trying to solve: > > We all know that LRU is try to solve the question of "what are the > pages recently accessed?", > so its engouth to use pte bits to approximate. > > However, the numa balancing problem is fundamentally like this: > > In some time unit, > > W = pages_accessed * average_page_access_frequence > > We are trying to move process to the node having max W, right? > > Andrea's patch can only approximate the pages_accessed number in a > time unit(scan interval), > I don't think it can catch even 1% of average_page_access_frequence > on a busy workload. > Blindly assuming that all the pages' average_page_access_frequence is Oh, sorry for my typo, I mean "frequency". > the same is seemly > broken to me. > > Sometimes, it's good to have a good view of your problem before > spending a lot time coding. > >> >> -- >> 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/ . >> Don't email: <a hrefmailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- 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/ . Don't email: <a href