Il 01/03/2013 00:22, Michael R. Hines ha scritto:te > Hi, > > Currently migration_bitmap_sync() is very expensive: on the order of > 15-20 milliseconds by my count using timestamps (for a simple 2GB ram > virtual machine). > Until new EPT processor versions come out in 2014, we need software > support for cutting this time down much lower........by at least an > order of magnitude. > > Would anyone be opposed to me writing a patch that creates N threads and > dividing up the migration_bitmap_sync() function to have the dirty page > scanning run in parallel?
Yes, that's a possibility. You can make a quick prototype using OpenMP. But Juan is working on making the dirty bitmap really a bitmap (not a "bytemap"). That should speed up migration_bitmap_sync by a factor of 64 (i.e. sizeof(long)*8). Paolo
