> On Thu, Nov 29, 2018 at 1:46 PM Casey Bodley <cbodley@xxxxxxxxxx> wrote: > > > > Bufferlist is a common theme in Mark's weekly performance meetings, and > > today's was no exception. Radoslaw highlighted the cost of atomic ref > > counting associated with sharing buffers, and there was broad agreement > > that the seastar osd's data path should avoid using bufferlist entirely > > for that reason. > > > > However, one choice that I made in the design of the seastar messenger > > was to use Ceph's existing bufferlist-based Message types so that their > > encode/decode wouldn't diverge between the seastar osd and its librados > > clients and peers like ceph-mon/mgr. > > > > In order to create a bufferlist-free data path, we'll need to find some > > abstraction that allows Message types to define a serialization format > > that can work both for bufferlist and for seastar's native buffer types > > - whether that covers all Message types, or just some subset of > > important ones like MOSDOp/Reply. > > > > Any thoughts on what this could look like? > > > > Casey On Thu, Nov 29, 2018 at 2:32 PM Noah Watkins <nwatkins@xxxxxxxxxx> wrote: > > Potentially stupid question... if there exists a buffer container that > can work in the new data path _without reference counting_, why not > create a bufferlist super class that doesn't do reference counting? Or even just let seastar wrap its own buffers in a new buffer ptr type and generate a new bufferlist when it passes that data into the non-seastar-ized code? -Greg
