DPDK Thash: Principles and Appliances

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" summary

DPDK thash implements a way to force RSS to deliver specific flows by computing minimal bit flips in a tuple and installing a crafted RSS key; the library precomputes a reverse complementary table mapping every ephemeral port to the XOR mask and uses a bitmap plus a flow-redirection table to avoid expensive per-connection hash loops. Integration with an F-stack/FreeBSD TCP stack shows much better scaling (tested up to 16 workers, 64-entry redirect table example) and near-linear throughput compared with the fallback that collapses under many threads.

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" chapters (17)

1. 0:00Introduction to DPDK Thash
2. 1:04Problems in multi-threaded environments
3. 2:11How RSS technology works
4. 3:15Predictable RSS and its use
5. 5:27Source NAT example
6. 7:35Why predictable RSS works
7. 8:19Ongoing work in DPDK Thash
8. 9:02Inferring RXQ from local port
9. 12:11FST project overview
10. 13:37Using Thash for local port hash
11. 16:26Building reverse complementary table
12. 17:33Reserving local ports in FST
13. 19:41Flow table for redirection
14. 20:44Solving three key problems
15. 21:08Performance results with IPv4/IPv6
16. 22:17Real-world example with Nginx
17. 23:37Q&A on RSS security

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