commit ee7e8d55c5c2c727b66e0518a8ec91d4a4a40162
author Todd Wang <toddw@google.com> Wed May 18 03:53:55 2016 -0700
committer Todd Wang <toddw@google.com> Wed May 18 17:31:50 2016 +0000
tree 1af4bd15a28ad85448adc1804b18769d62f9b86d
parent 67e34c8f8c877e1f0794cf66a8506bfc5e421b98

vdl: Add generated vars for TypeOf, for better performance.

Also changed vdl.Decoder.StartValue to take a *vdl.Type argument,
and perform the compatibility check.  This gives up to an
additional 10% improvement, and makes it easier to optimize the
compatibility check in the future, since it's now only performed
by the 3 decoders (vom, vdl.Value and vdl.pipe).

Some numbers.  In general all the generated stuff gets better:
                                 old ns/op  new ns/op   delta
RpcRequestZeroSingleShotEncode     51010      41028    -19.57%
RpcRequestZeroRepeatedEncode         302        194    -35.76%
RpcRequestZeroSingleShotDecode      1962       1636    -16.62%
RpcRequestZeroRepeatedDecode         484        281    -41.94%
RpcRequestFullSingleShotEncode     63755      47481    -25.53%
RpcRequestFullRepeatedEncode        9407       5558    -40.92%
RpcRequestFullSingleShotDecode     58886      58863     -0.04%
RpcRequestFullRepeatedDecode       55303      54106     -2.16%
RpcResponseZeroSingleShotEncode    51700      40604    -21.46%
RpcResponseZeroRepeatedEncode        635        514    -19.06%
RpcResponseZeroSingleShotDecode     2026       1755    -13.38%
RpcResponseZeroRepeatedDecode        524        304    -41.98%
RpcResponseFullSingleShotEncode   106038      91816    -13.41%
RpcResponseFullRepeatedEncode      44273      42005     -5.12%
RpcResponseFullSingleShotDecode    43271      42635     -1.47%
RpcResponseFullRepeatedDecode      38608      37251     -3.51%

For some reason, the reflect version of large-list single-shot
encoding gets much worse.  I'm not sure why.  But I'm going to
ignore that for now, since I think there's plenty of other
optimizations we can explore.
                                  old ns/op  new ns/op   delta
LargeListSingleShotEncodeReflect   19279360   21696617  +12.54%
LargeListRepeatedEncodeReflect     19055693   19550742   +2.60%
LargeListSingleShotDecodeReflect   34161615   32556162   -4.70%
LargeListRepeatedDecodeReflect     33647837   31846309   -5.35%
LargeListSingleShotEncode           3951128    3984021   +0.83%
LargeListRepeatedEncode             3870694    3895734   +0.65%
LargeListSingleShotDecode           5221050    5465362   +4.68%
LargeListRepeatedDecode             5211915    5246888   +0.67%

MultiPart: 3/5
Change-Id: I655e0cf3662f75aaf4dd54628fcc906fbc138d62