HERD

1. Reading
“Using RDMA Efficiently
for Key-Value Services”[1]
@syoyo
Thursday, August 7, 14

2. Overview
• KVS(GET/PUT) + RDMA
• 26 million key-value op per second
• 5 us average latency
• 1 key-value item size <= 1024 bytes
• 2x faster than previous method
Thursday, August 7, 14

3. Previous work
• Pilaf : C. Mitchell,Y. Geng, and J. Li. Using One-Sided
RDMA Reads to Build a Fast, CPU-Efficient Key-Value
Store. In USENIX ATC, 2013.
• FaRM :
A.Dragojevic,D.Narayanan,O.Hodson,andM.Castro.
FaRM: Fast Remote Memory. In USENIX NSDI, 2014.
• MICA: H. Lim, D. Han, D. G.Andersen, and M.
Kaminsky. MICA:A Holistic Approach to Fast In-
Memory Key-Value Storage. In USENIX NSDI, 2014.
Thursday, August 7, 14

4. • Use RDMA WRITE instead of RDMA
READ
• Half round trip latency
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5. ServerClient
Client
RDMA WRITE UC
RDMA WRITE UC
polling
SEND UD
SEND UD
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6. Op
• 1) client -> server request(PUT, GET) using
RDMA WRITE
• 2) server polls per-client memory region to
check request
• 3) Do key-value lookup
• 4) server -> client reply using SEND
Thursday, August 7, 14

7. Evaluation
• Apt
• IB FDR(56 Gbps) ConnectX-3
• Susitna
• RoCE(40GbE CX-3 MX313A)
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12. References
• [1] https://www.cs.cmu.edu/~akalia/doc/
herd_readable.pdf
• https://github.com/efficient/HERD
Thursday, August 7, 14