Cliff Wickman <cpw-sJ/iWh9BUns at public.gmane.org> writes: > From: Cliff Wickman <cpw-sJ/iWh9BUns at public.gmane.org> > > The copy of /proc/vmcore to a user buffer proceeds much faster > if the kernel addresses memory as cached. > > With this patch we have seen an increase in transfer rate from less than > 15MB/s to 80-460MB/s, depending on size of the transfer. This makes > a big difference in time needed to save a system dump. > > (Does anyone know of a reason why copy_oldmem_page() would need > to use uncached addresses?) > > Diffed against 2.6.36-rc3 I had a similar patch somewhere in my private kernels, yes it's a big win. I think it was simply a bug that was added when ioremap was changed to default to uncached. -Andi -- ak at linux.intel.com -- Speaking for myself only.
