1. Fast forwarding table lookup exploiting GPU memory architecture Author : Youngjun Lee,Minseon Jeong,Sanghwan Lee,Eun-Jin Im Publisher : Information and Communication Technology Convergence (ICTC), 2010 International Conference on Presenter: Gang Chi Date: 2015/1/7 Department of Computer Science and Information Engineering National Cheng Kung University, Taiwan R.O.C.

2. Introduction Packet Shader, a software router system, uses GPU to exploit GPU’s extensive parallelism, shows higher performance compared to other existing software routers. However, Packet Shader does not utilize the memory architecture in the GPU system. This paper provides a method to exploit GPU memory architecture. National Cheng Kung University CSIE Computer & Internet Architecture Lab 2

3. GPU Memory Architecture National Cheng Kung University CSIE Computer & Internet Architecture Lab 3 TypeLocationAccess cycleSize Global memoryOff-chip>1001~32GB per GPU L1 cacheOn-chip1~3216 or 48KB per SMX L2 cacheOn-chip1~3264KB per SMX RegistersOn-chipn/a32-bit x 65536 per SMX

4. GPU Memory Architecture Memory type in GPU Global Memory : high bandwidth,large size, but need more cycle to access. Constant memory,texture memory : two small pieces of memory and can be cached by on-chip read-only cache of each SMX. National Cheng Kung University CSIE Computer & Internet Architecture Lab 4

5. Fast Forwarding Table Lookup Store the whole forwarding table in the global memory. Create index in the constant memory(64KB). National Cheng Kung University CSIE Computer & Internet Architecture Lab 5

6. Fast Forwarding Table Lookup Currently the number of active BGP entries is about 340,000. The number of prefixes with length of 16 or less is 4.18%,24 is about 52%.Thus we expand all the prefixes of length less than 24 into multiple /24 prefixes. The number of prefixes is still less than one million(needs 20 bits to identify). National Cheng Kung University CSIE Computer & Internet Architecture Lab 6

7. Fast Forwarding Table Lookup National Cheng Kung University CSIE Computer & Internet Architecture Lab 7

8. Fast Forwarding Table Lookup National Cheng Kung University CSIE Computer & Internet Architecture Lab 8

9. Data Structure National Cheng Kung University CSIE Computer & Internet Architecture Lab 9

10. Data Structure National Cheng Kung University CSIE Computer & Internet Architecture Lab 10

11. Data Structure National Cheng Kung University CSIE Computer & Internet Architecture Lab 11

12. Example National Cheng Kung University CSIE Computer & Internet Architecture Lab 12

13. GPU Spec (1/2) National Cheng Kung University CSIE Computer & Internet Architecture Lab 13

14. GPU Spec (2/2) National Cheng Kung University CSIE Computer & Internet Architecture Lab 14

15. Exprimental Result National Cheng Kung University CSIE Computer & Internet Architecture Lab 15