Review Neko to increase performance and reduce memory usage

[rschwietzke]

This is just a bookmark for my ongoing task of tuning without larger rewrites. So far, we got to this:

Wikipedia DE Homepage, DOM Parser, JDK 17, JDK 8 target

Old, v3.8.0

Benchmark                                               Mode  Cnt      Score     Error   Units
HtmlParser_v380_Benchmark.domParser                     avgt    3  1,596,511 ± 136,413   ns/op
HtmlParser_v380_Benchmark.domParser:gc.alloc.rate.norm  avgt    3  1,091,867 ±   1,868    B/op

New, JDK 8 target

Benchmark                                               Mode  Cnt      Score     Error   Units
HtmlParser_v380_Benchmark.domParser                     avgt    3  1,178,706 ± 130,720   ns/op
HtmlParser_v380_Benchmark.domParser:gc.alloc.rate.norm  avgt    3    870,992 ±       0    B/op

New, JDK 11 target

Benchmark                                               Mode  Cnt      Score     Error   Units
HtmlParser_v380_Benchmark.domParser                     avgt    3  1,165,087 ± 112,361   ns/op
HtmlParser_v380_Benchmark.domParser:gc.alloc.rate.norm  avgt    3    870,656 ±       0    B/op

Summary: 25% faster and 20% less memory is needed. There are 1-2% more performance in a JDK 11 compile than a JDK 8 one due to improvements of the JDK 11 code generation (no accessor methods for inner classes anymore).

[rschwietzke]

Quick update. Lastest master rebase. Test cases are green for Neko.

Wikipedia DE Homepage, DOM Parser, JDK 17, JDK 8 target

Neko 3.9.0

Benchmark                                                  Mode  Cnt        Score        Error   Units
HtmlParser_v380_Benchmark.domParser                        avgt    3  1496302.471 ±  83074.746   ns/op
HtmlParser_v380_Benchmark.domParser:gc.alloc.rate.norm     avgt    3  1089728.077 ±      0.004    B/op

HtmlParser_v380_Benchmark.saxParser                        avgt    3  1279731.554 ± 293476.329   ns/op
HtmlParser_v380_Benchmark.saxParser:gc.alloc.rate.norm     avgt    3   739072.066 ±      0.015    B/op

HtmlParser_v380_Benchmark.simpleParser                     avgt    3  1214197.735 ±  41572.272   ns/op
HtmlParser_v380_Benchmark.simpleParser:gc.alloc.rate.norm  avgt    3   684296.062 ±      0.002    B/op

Neko Tuning Branch

Benchmark                                                  Mode  Cnt        Score        Error   Units
HtmlParser_v380_Benchmark.domParser                        avgt    3  1243972.026 ± 206167.723   ns/op
HtmlParser_v380_Benchmark.domParser:gc.alloc.rate.norm     avgt    3   877664.065 ±      0.034    B/op

HtmlParser_v380_Benchmark.saxParser                        avgt    3   948056.111 ±  65846.940   ns/op
HtmlParser_v380_Benchmark.saxParser:gc.alloc.rate.norm     avgt    3   597336.049 ±      0.003    B/op

HtmlParser_v380_Benchmark.simpleParser                     avgt    3   998957.186 ±  35800.702   ns/op
HtmlParser_v380_Benchmark.simpleParser:gc.alloc.rate.norm  avgt    3   597168.051 ±      0.002    B/op

[rschwietzke]

Final results as part of PR #73.
Benchmark used: HtmlParser_v380_Benchmark. Benchmark suite will form its own repo soon.

Runtimes always improve, up to 30%, memory churn improves up to 15%. For really small HTML, we are using more memory, but still improving runtimes.

Data

Benchmark	(file)	v3.9.0	Tuned	Units	Diff
domParser	simple.html	54,344	46,837	ns/op	86 %
domParser:gc.alloc.rate.norm	simple.html	66,216	80,536	B/op	122 %
domParser	small-xc-homepage.html	370,874	291,392	ns/op	79 %
domParser:gc.alloc.rate.norm	small-xc-homepage.html	314,224	286,032	B/op	91 %
domParser	wikipedia-de-hp.html	1,537,761	1,168,103	ns/op	76 %
domParser:gc.alloc.rate.norm	wikipedia-de-hp.html	1,089,728	877,328	B/op	81 %
domParser	puma-de-hp.html	9,748,265	6,782,239	ns/op	70 %
domParser:gc.alloc.rate.norm	puma-de-hp.html	5,777,001	4,911,984	B/op	85 %
saxParser	simple.html	52,867	43,900	ns/op	83 %
saxParser:gc.alloc.rate.norm	simple.html	73,024	88,320	B/op	121 %
saxParser	small-xc-homepage.html	310,194	232,592	ns/op	75 %
saxParser:gc.alloc.rate.norm	small-xc-homepage.html	241,624	215,040	B/op	89 %
saxParser	wikipedia-de-hp.html	1,251,809	1,000,298	ns/op	80 %
saxParser:gc.alloc.rate.norm	wikipedia-de-hp.html	739,096	596,624	B/op	81 %
saxParser	puma-de-hp.html	7,829,730	5,712,766	ns/op	73 %
saxParser:gc.alloc.rate.norm	puma-de-hp.html	3,501,952	2,894,192	B/op	83 %
simpleParser	simple.html	49,901	43,841	ns/op	88 %
simpleParser:gc.alloc.rate.norm	simple.html	72,896	88,200	B/op	121 %
simpleParser	small-xc-homepage.html	293,126	261,387	ns/op	89 %
simpleParser:gc.alloc.rate.norm	small-xc-homepage.html	210,432	214,928	B/op	102 %
simpleParser	wikipedia-de-hp.html	1,233,736	993,234	ns/op	81 %
simpleParser:gc.alloc.rate.norm	wikipedia-de-hp.html	685,184	597,120	B/op	87 %
simpleParser	puma-de-hp.html	7,422,030	5,894,724	ns/op	79 %
simpleParser:gc.alloc.rate.norm	puma-de-hp.html	3,201,896	2,894,186	B/op	90 %

[rschwietzke]

Starting to use https://github.com/HtmlUnit/htmlunit-jmh-benchmarks for benchmarking. Here are the first data points just to study things. All on an 8core-Hetzner AMD cloud machine in Finland.

Test Stability First

# Benchmark: org.htmlunit.jmh.benchmarks.htmlunit.AverageHtmlBenchmark.averageHtml
# Warmup Iteration   1: 588310.199 ns/op
# Warmup Iteration   2: 422319.354 ns/op
# Warmup Iteration   3: 404832.667 ns/op
# Warmup Iteration   4: 404149.344 ns/op
# Warmup Iteration   5: 396249.051 ns/op
Iteration   1: 403408.458 ns/op
Iteration   2: 404042.486 ns/op
Iteration   3: 403162.067 ns/op

# Benchmark: org.htmlunit.jmh.benchmarks.htmlunit.LargeDocumentManyAttributes.largeHtmlManyAttriubutes
# Warmup Iteration   1: 772721.230 ns/op
# Warmup Iteration   2: 614578.110 ns/op
# Warmup Iteration   3: 590680.022 ns/op
# Warmup Iteration   4: 586936.761 ns/op
# Warmup Iteration   5: 586906.498 ns/op
Iteration   1: 588491.532 ns/op
Iteration   2: 589705.188 ns/op
Iteration   3: 597832.926 ns/op

# Benchmark: org.htmlunit.jmh.benchmarks.htmlunit.LargeDocumentNoAttributes.largeHtmlNoAttributes
# Warmup Iteration   1: 284626.756 ns/op
# Warmup Iteration   2: 215568.106 ns/op
# Warmup Iteration   3: 213884.361 ns/op
# Warmup Iteration   4: 218684.786 ns/op
# Warmup Iteration   5: 215844.534 ns/op
Iteration   1: 215480.792 ns/op
Iteration   2: 215191.652 ns/op
Iteration   3: 215032.429 ns/op

# Benchmark: org.htmlunit.jmh.benchmarks.htmlunit.MinimalDocumentBenchmark.minimalHtml
# Warmup Iteration   1: 14560.742 ns/op
# Warmup Iteration   2: 10900.473 ns/op
# Warmup Iteration   3: 10872.220 ns/op
# Warmup Iteration   4: 10875.081 ns/op
# Warmup Iteration   5: 10889.511 ns/op
Iteration   1: 10914.296 ns/op
Iteration   2: 10891.577 ns/op
Iteration   3: 10933.147 ns/op

Benchmark                                             Mode  Cnt       Score       Error  Units
AverageHtmlBenchmark.averageHtml                      avgt    3  403537.670 ±  8286.479  ns/op
LargeDocumentManyAttributes.largeHtmlManyAttriubutes  avgt    3  592009.882 ± 92665.036  ns/op
LargeDocumentNoAttributes.largeHtmlNoAttributes       avgt    3  215234.957 ±  4146.738  ns/op
MinimalDocumentBenchmark.minimalHtml                  avgt    3   10913.007 ±   379.743  ns/op
```