[WIP] refactor: enhance decode performance

[gxcsoccer]

初步优化了下 number, date 和 string，性能和孝达的 fast hessian2 差不多了

  Fast hessian2 decode: number x 10,408,116 ops/sec ±1.10% (87 runs sampled)
  Fast hessian2 decode: date   x  4,139,701 ops/sec ±1.04% (88 runs sampled)
  Fast hessian2 decode: string x  1,843,122 ops/sec ±5.17% (61 runs sampled)

  js hessian2 decode: number x 11,456,920 ops/sec ±1.18% (88 runs sampled)
  js hessian2 decode: date   x  3,964,458 ops/sec ±1.14% (90 runs sampled)
  js hessian2 decode: string x  1,617,342 ops/sec ±1.08% (93 runs sampled)

[mention-bot]

@gxcsoccer, thanks for your PR! By analyzing the history of the files in this pull request, we identified @dead-horse and @fengmk2 to be potential reviewers.

[pmq20]

初步优化了下 number, date 和 string，性能和孝达的 fast hessian2 差不多了

这俩组数据要在同一台机器 && Node.js version 上跑才有意义。我试一下我的机器 && node 8-pre

[pmq20]

@gxcsoccer 同一台机器，同样的 node 版本下：

  node version: v8.0.0-pre

  hessian2 decode: number x 4,721,288 ops/sec ±0.54% (87 runs sampled)
  hessian2 decode: date   x 2,599,811 ops/sec ±0.61% (92 runs sampled)
  hessian2 decode: string x   557,185 ops/sec ±1.01% (88 runs sampled)

  Fast hessian2 decode: number x 9,706,914 ops/sec ±1.41% (84 runs sampled)
  Fast hessian2 decode: date   x 3,861,312 ops/sec ±1.18% (86 runs sampled)
  Fast hessian2 decode: string x 1,671,423 ops/sec ±5.69% (60 runs sampled)

[fengmk2]

@gxcsoccer 比之前的 js 版本优化多少？加上对比

[fengmk2]

ci 加上 node 7

[codecov[bot]]

Codecov Report

Merging #74 into master will decrease coverage by 0.57%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #74      +/-   ##
==========================================
- Coverage   96.09%   95.51%   -0.58%     
==========================================
  Files           7        7              
  Lines        1076     1093      +17     
  Branches      202      204       +2     
==========================================
+ Hits         1034     1044      +10     
- Misses         42       49       +7

Impacted Files	Coverage Δ
index.js	100% <100%> (ø)	:arrow_up:
lib/v1/decoder.js	98.33% <100%> (+0.07%)	:arrow_up:
lib/v2/decoder.js	92.52% <100%> (+0.13%)	:arrow_up:
lib/utils.js	83.33% <0%> (-16.67%)	:arrow_down:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 1bea205...f8ad41a. Read the comment docs.

[gxcsoccer]

@pmq20 你跑的时候 byte 还没有合并，现在再跑跑试试

[gxcsoccer]

优化前

  Hessian Decode Benchmark
  node version: v7.10.0, date: Thu May 11 2017 16:53:41 GMT+0800 (CST)
  Starting...
  3 tests completed.

  hessian2 decode: number x 1,647,104 ops/sec ±1.51% (83 runs sampled)
  hessian2 decode: date   x   412,326 ops/sec ±2.43% (81 runs sampled)
  hessian2 decode: string x   169,817 ops/sec ±1.93% (84 runs sampled)

优化后

  Hessian Decode Benchmark
  node version: v7.10.0, date: Thu May 11 2017 16:54:07 GMT+0800 (CST)
  Starting...
  3 tests completed.

  hessian2 decode: number x 9,965,533 ops/sec ±2.19% (85 runs sampled)
  hessian2 decode: date   x 3,342,223 ops/sec ±2.62% (81 runs sampled)
  hessian2 decode: string x 1,272,044 ops/sec ±1.73% (84 runs sampled)

[gxcsoccer]

number 和 string 的优化主要来自于 byte.get https://github.com/node-modules/byte/pull/25

[pmq20]

  hessian2 decode: number x 9,840,410 ops/sec ±1.10% (92 runs sampled)
  hessian2 decode: date   x 3,965,427 ops/sec ±0.47% (90 runs sampled)
  hessian2 decode: string x 1,473,963 ops/sec ±0.72% (91 runs sampled)

  Fast hessian2 decode: number x 10,883,935 ops/sec ±1.01% (91 runs sampled)
  Fast hessian2 decode: date   x  4,356,561 ops/sec ±0.88% (90 runs sampled)
  Fast hessian2 decode: string x  1,886,761 ops/sec ±4.78% (62 runs sampled)

[pmq20]

💯 确实性能和 fast hessian2 差不多了

[fengmk2]

@gxcsoccer 这周忙完继续搞这个，最近 rpc 比较多压力。