pions / srtp / 50

42%

master: 41%

Pull #6

travis-ci

Optimize session auth tag generation

I profiled my application and crypto/hmac.New was taking 5.71% of the
total CPU time. Since the session key does not change, you can call
crypto/hmac.Reset() instead of making a new object. This reuses previous
work done for the key.

With a separate generateAuthTag function for RTP/RTCP, it's now possible
to pass in the ROC instead of appending it to the buffer. This primarily
helps DecryptRTP, as it was otherwise doing an extra append just for the
ROC.

name                 old time/op    new time/op    delta
EncryptRTP-8           2.20µs ± 5%    2.00µs ± 4%   -9.00%
EncryptRTPInPlace-8    2.20µs ± 1%    1.97µs ± 5%  -10.52%
DecryptRTP-8           2.13µs ± 3%    1.79µs ± 4%  -16.18%

name                 old alloc/op   new alloc/op   delta
EncryptRTP-8           1.23kB ± 0%    0.79kB ± 0%  -36.04%
EncryptRTPInPlace-8    1.10kB ± 0%    0.66kB ± 0%  -40.22%
DecryptRTP-8           1.17kB ± 0%    0.69kB ± 0%  -40.75%

name                 old allocs/op  new allocs/op  delta
EncryptRTP-8             11.0 ± 0%       7.0 ± 0%  -36.36%
EncryptRTPInPlace-8      10.0 ± 0%       6.0 ± 0%  -40.00%
DecryptRTP-8             12.0 ± 0%       7.0 ± 0%  -41.67%

49 of 49 new or added lines in 3 files covered. (100.0%)

319 of 761 relevant lines covered (41.92%)

10.69 hits per line