Dan Malek <ppc6...@digitaldans.com> wrote on 2011/10/10 20:03:53: > > > On Oct 10, 2011, at 9:45 AM, Joakim Tjernlund wrote: > > > That is an easy port but I will have to do that blind. Would you > > mind take this for a spin on 2.4 first? > > My current system is running 2.6, so I don't have much > interested in testing 2.4
Too bad as I won't be able to run 2.6 at all. However, I just sent you a dry port to 3.0 of the large page stuff to you. Happy testing. > > > The more interesting part is if one should use other sized(16K or > > 512K) large pages too? > > My thought long ago was most of the 8xx systems have rather small > real memories, so the larger pages, especially 512K may be too wasteful. > I've always been a fan of keeping the TLB handlers tiny and simple, > rather then spending the instructions doing complex replacements. > Remember, this also affects the I- and D-cache, so a more frequent > and trivial PTE update could very well gain larger system performance > than the management of larger pages with more complex code. > With all of the bug fix code in the handlers, maybe a larger page would > be better. > > > Those should be useful for user space but it is a lot of work. I > > haven't checked > > what large page support for user space is in 2.6 for ppc though. > > The 2.6/3.0 kernel supports different, but fixed, page sizes. IIRC, > anything > over 64K may require distribution rebuilding to realign code/data > sections > to more restrictive boundaries. Maybe a 16K page would show some > benefit. > I'll try to make some time to play with it. Unfortunately 3.0 does not have any free PTE bits now. I had to move _PAGE_SPECIAL to the last available one as the new _PAGE_PSE needed its place. Don't know what _PAGE_SPECIAL is but if it cannot be removed one can always skip _PAGE_WRITETHRU again. Jocke _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
