Hi all, This patch set adds to libosmocore an optimized Viterbi decodeer for architecture specific (Intel SSE) and non-specific cases. The implementation covers codes with constraint lengths of K=5 and K=7 and rates 1/4 to 3/4, which make up the majority of GSM use cases. Speedup from the current implementation is in the range of 5 to 20 depending on the processor and code type. API is unchanged. Tested on Haswell (i7-4770K) and Atom (D2550). Additional test codes from osmo-bts are included. Further tests for AWGN bit-error-rate and benchmarks can be found in the following repository. https://github.com/ttsou/osmo-conv-test Here are some examples. Bit error test for GPRS CS2 with SNR of 5 dB and 100000 bursts. $ ./conv_test -c 2 -e -r 5 -i 100000 ================================================= [+] Testing: GPRS CS2 [.] Specs: (N=2, K=5, non-recursive, flushed, not punctured) [.] Input length : ret = 290 exp = 290 -> OK [.] Output length : ret = 588 exp = 588 -> OK [.] BER tests: [..] Testing base: [..] Input BER.......................... 0.042443 [..] Output BER......................... 0.000006 [..] Output FER......................... 0.001350 (135) [..] Testing SIMD: [..] Input BER.......................... 0.042460 [..] Output BER......................... 0.000005 [..] Output FER......................... 0.001240 (124) Timed AFS benchmark with 8 threads and 100000 bursts per thread. $ ./conv_test -b -c 10 -j 8 -i 100000 ================================================= [+] Testing: GSM TCH/AFS 6.7 [.] Specs: (N=4, K=5, recursive, flushed, punctured) [.] Input length : ret = 140 exp = 140 -> OK [.] Output length : ret = 448 exp = 448 -> OK [.] Performance benchmark: [..] Encoding / Decoding 800000 bursts on 8 thread(s): [..] Testing base: [..] Elapsed time....................... 4.320001 secs [..] Rate............................... 25.925920 Mbps [..] Testing SIMD: [..] Elapsed time....................... 0.458272 secs [..] Rate............................... 244.396341 Mbps [..] Speedup............................ 9.426718 -TT

On 01 May 2014, at 20:02, Tom Tsou <tom(a)tsou.cc> wrote:

The patch for additional test codes was already posted and is run with 'make check'. Those cases mostly serve as regression tests. For AWGN tests, I feel less certain that wireless channel modeling belong in libosmocore. The error rate simulations will not fit the current make check model since they are probabilistic and non-deterministic by definition.

On 18 May 2015, at 21:23, Tom Tsou <tom(a)tsou.cc> wrote: Hi Holger,

On Sun, May 17, 2015 at 10:05 AM, Holger Freyther <holger(a)freyther.de> wrote: There was some discussion, but we never got around to completing the review. If there is still interest, we can revive that discussion.

On 20 May 2015, at 08:28, Alexander Chemeris <alexander.chemeris(a)gmail.com> wrote: Strictly speaking, it speeds up lower parts of osmo-bts. And yes, it's a great improvement and I hope the review can be finished and patch merged. Viterbi is the most CPU hungry part of osmo-bts on UmTRX and other SDR platforms.

On 23 May 2015, at 20:56, Sylvain Munaut <246tnt(a)gmail.com> wrote:

Yeah, it's my bad …

Recent activity around convolutional coding has reminded me about this lost diamond. Just wondering if there is a chance to resolve the critical issues and get this merged?