> Joakim Tjernlund wrote: > > > I have been playing with the copy_page() function in arch/ppc/kernel/misc.S > > and gained about 30% speed up for my mpc860, rev D4 MHz. > > Have you found the discussion in linuxppc-dev about the work Paul has done > on this in general for PowerPC? It may help avoid repeating some work and > provide some guidance.....
I have searched but I did not find anything conclusive. Pointers? > And don't forget....many applications aren't heavily 'copy-centric' and it > may be beneficial to not blow away the caches in those cases. That is, if If you are referring to the copy_page() that I attached in my first mail, then yes it uses more icache, but if you have seen my later post where I took it back and stated that just enabling dcbz in the existing version of copy_page() would give the same speed up, I don't follow you. How am I wasting caches? In the end I would like to modify copy_tofrom_user() so that dcbz is used on kernel space addresses but not on user space without adding a lot of code. Ideas welcome. > you apply systems engineering methods to your testing instead of just focusing > on such a low level detail, you may discover you are wasting your time and > from an overall system application you may be providing little benefit or > even a overall degradation in system performance. I am just trying make 8xx perform a little better and I focus on areas I know something about such as crc32, the enet.c driver and in this case various memory copy stuff. Hopefully the end result will be useful to me and others. Jocke ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
