Le 10/07/12 16:51, David Kuehling a écrit : >>>>>> "Werner" == Werner Almesberger <wer...@almesberger.net> writes: > >> Yann Sionneau wrote: >>> *TLB size : 1024 entries > >> 1024+1024 is pretty big. I found Longsoon 2E has 16+64 [1], Itanic has >> 96+128, PowerPC 405 has 64 (unified ?) [3], only Intel i7 comes >> somewhat close with 576 entries per core. [4] > > Note that Loongson has 16kB pages (per default under Linux, AFAIR). Any > reason we stick to 4kB pages?
Milkymist One board has 128 MB of DDR400 SDRAM. Which means 32768 pages (if page size is 4 kB). I don't know the advantages of having big pages but I guess it's better for fragmentation to have smaller pages since it allows to have smaller slices. If you have 16 kB pages, each "page allocation" eats you up 16 kB, instead of 4 kB but maybe you don't need that much. One advantage of having bigger page size is that when you have a LOT of RAM, you have less struct page and therefore "managing the pages" eats less RAM. But we don't have so much RAM therefore we are fine. Assuming sizeof(struct page) == 40 bytes managing 4 kB pages for M1 costs us : 40 * 32768 = 1.24 MB What are other advantages in using 16 kB pages ? > Might be an anachronism, and M1 has pretty > much RAM anyways. > > cheers, > > David > > > > _______________________________________________ > http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org > IRC: #milkymist@Freenode > _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkymist@Freenode
