A single backup operation (ClusterPerf with 100-byte writes, 1 master, 3 backups)
Averaged over 1912 sample timelines:
0 us --- Begin backup | | 2.0 us --- First write RPC sent out | | 3.3 us --- Second write RPC sent out | | 4.5 us --- Third write RPC sent out | | | [~ 4 us "dead time"] | | 8.6 us --- First write RPC completes (duration: 6.6 us) | 9.8 us --- Second write RPC completes (duration: 6.5 us) | 10.8 us --- Third write RPC completes (duration: 6.3 us) 10.9 us --- End backup |
Major time sinks in issue path
Simple program to benchmark 56-byte write.
Averaged over 100 samples.
Using RDMA: 2.50495 us
Using RDMA: 4.866 us
We see that a one-way RDMA easily beats the round-trip IB send's currently used RAMCloud RPC.