On 9 Jun 2012, at 11:05, Konstantin Belousov wrote: > First, there is nothing which would prevent demotion from happens while > you iterate over the map, so you could get funyy numbers, like 42 superpages > for 2M region with your method. > > Second, the superpage size if machine-depended, and even single machine > could support differently sized superpage. For amd64, hardware can support > 2M and 1G pages, and for i386 you can get 4M or 2M depending on PAE config. > > And last, I in fact do not see much use for any 'superpage count'. Would I > would like to see is the TLB miss count for a region. Then I could estimate > whether superpage enabling provided some advantage. Just as a note, if > there were no accesses to a region after promotion, then promotion is > the waste. > > Anyway, please do not consider this as discouraging you from doing a > useful work.
Despite the rendering and underlying semantic issues, I admit that I would like to know when superpages are being used by processes -- perhaps enough information to construct a histogram of page sizes for each mapping. Robert_______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
