On Thu, Nov 13, 2014 at 06:33:14PM +0100, Thomas Monjalon wrote: > Any comment on these patches? > > 2014-09-03 12:05, Yerden Zhumabekov: > > As SSE4.2 provides CRC32 instructions with either 32 and 64 bit operands, > > new rte_hash_crc_8byte() call assisted with _mm_crc32_u64 intrinsic may be > > useful. > > > > Then, rte_hash_crc() function is redesigned to take advantage of both 32 > > and 64 bit operands. This improves the function's performance significantly. > > > > Results of my test run on a single CPU core are below. > > > > CPU: Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz > > Number of iterations/chunks: 52428800 > > Chunk size: 24 > > rte_hash_crc: 0.379 sec, hash: 0x14c64e11 > > rte_hash_crc_new: 0.253 sec, hash: 0x14c64e11 > > Chunk size: 25 > > rte_hash_crc: 0.442 sec, hash: 0xa9afc779 > > rte_hash_crc_new: 0.316 sec, hash: 0xa9afc779 > > Chunk size: 26 > > rte_hash_crc: 0.442 sec, hash: 0x92f2284b > > rte_hash_crc_new: 0.316 sec, hash: 0x92f2284b > > Chunk size: 27 > > rte_hash_crc: 0.442 sec, hash: 0x7c4655ff > > rte_hash_crc_new: 0.316 sec, hash: 0x7c4655ff > > Chunk size: 28 > > rte_hash_crc: 0.442 sec, hash: 0xf577c6b4 > > rte_hash_crc_new: 0.316 sec, hash: 0xf577c6b4 > > Chunk size: 29 > > rte_hash_crc: 0.505 sec, hash: 0x6e18ba55 > > rte_hash_crc_new: 0.337 sec, hash: 0x6e18ba55 > > Chunk size: 30 > > rte_hash_crc: 0.505 sec, hash: 0x35f07dbb > > rte_hash_crc_new: 0.337 sec, hash: 0x35f07dbb > > Chunk size: 31 > > rte_hash_crc: 0.505 sec, hash: 0x1bf2ee8c > > rte_hash_crc_new: 0.337 sec, hash: 0x1bf2ee8c > > > > Yerden Zhumabekov (2): > > hash: add new rte_hash_crc_8byte call > > hash: rte_hash_crc uses 8- and 4-byte CRC32 intrinsics > > > > lib/librte_hash/rte_hash_crc.h | 47 > > +++++++++++++++++++++++++++++++++------- > > 1 file changed, 39 insertions(+), 8 deletions(-) > > Yeah, sorry I didn't speak up earlier. I meant to ask if the __mm_crc_u64 intrinsic will emit software emulated versions of the sse4.2 instruction in the event that you build with a config that doesn't enable sse4.2? If not, then NAK, since this will break on the default build. In that event you'll have to modify the new function to do a runtime cpu flags check to either just use the instruction inlined with some asm, or emulate it in software.
Neil
