On Sun, Sep 07, 2014 at 02:41:53PM +0300, Michael S. Tsirkin wrote: > > Signed-off-by: Christoph Hellwig <[email protected]> > > OK so this is an optimization patch right? > What kind of performance gain is observed with it?
None. I actually wrote it when the block layer had a bug when dm was used on top of the !merge case, and I decided to send it out as there had been no discussion about disabling this by default on the existing blk-mq drivers. At least for my qemu/kvm setup it doesn't make a difference either way, although not doing the cheap merge doesn't like the right kind of optimization to me. _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
