[dpdk-dev] [PATCH v5 0/7] rte_hash_crc reworked to be platform-independent

Thomas Monjalon thomas.monjalon at 6wind.com
Thu Nov 27 22:04:41 CET 2014


2014-11-20 11:15, Yerden Zhumabekov:
> These patches bring a fallback mechanism to ensure that CRC32 hash is calculated regardless of hardware support from CPU (i.e. SSE4.2 intrinsics).
> Performance is also improved by slicing data in 8 bytes.
> 
> Patches were tested on machines either with and without SSE4.2 support.
> 
> Software implementation seems to be about 4-5 times slower than SSE4.2-enabled one. Of course, they return identical results.
> 
> Summary of changes:
> * added CRC32 software implementation, which is used as a fallback in case SSE4.2 is not available, or if SSE4.2 is intentionally disabled.
> * added rte_hash_crc_set_alg() function to control availability of SSE4.2.
> * added rte_hash_crc_8byte() function to calculate CRC32 on 8-byte operand.
> * reworked rte_hash_crc() function which leverages both versions of CRC32 hash calculation functions with 4 and 8-byte operands.
> * removed compile-time checks from test_hash_perf and test_hash.
> * setting default algorithm implementation as a constructor while application startup.
> * SSE4.2 intrinsics are implemented through inline assembly code.
> * added additional run-time check for 64-bit support.

So you don't want to use the target attribute as suggested by Konstantin?

Why the discussion ended without any acknowledgement?

-- 
Thomas


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