On Mon, 11 May 2015, Deneau, Tom wrote: > I have noticed the following while running rados bench seq read tests with a 40M object size > > single rados bench, 4 concurrent ops, bandwidth = 190 MB/s > 4 copies of rados bench, 1 concurrent op each, aggregate bandwidth = 310 MB/s > > and in fact the single rados bench seems limited to 190, no matter how many concurrent ops. > > I don't see this kind of behavior with a 4M object size. > > (The above are with caches dropped on the osd targets) > > It doesn't seem to be related to the total number of bytes being processed by the single > because if I don't drop the caches, both the single rados bench and the 4-copy rados bench > get much higher numbers (600 vs. 900) but still the single rados bench appears limited, no matter > how many concurrent ops are used. > > Is there kind of throttling going on by design here? It might be the librados throttles: OPTION(objecter_inflight_op_bytes, OPT_U64, 1024*1024*100) // max in-flight data (both directions) OPTION(objecter_inflight_ops, OPT_U64, 1024) // max in-flight ios IIRC these only affect librados.. which would include 'rados bench'. sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
