Hi Matthias... On Wed, Feb 8, 2012 at 17:59, Matthias Brugger <matthias.bgg@googlemail.com> wrote:
If I understand the patch which introduces the blk tracer to ftrace (http://lwn.net/Articles/315508/) just uses the blktrace interface. So I wonder why using this influences the I/O behaviour.
Then I am completely clueless now. Better consult with qemu-devel mailing list. PS: just crossed my mind, maybe ftrace that uses blktrace is actually tracing the qemu's virtio. Whereas blktrace is tracing the physical block access. This is just speculation, after re-reading that you use virtio and disable write caching. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com