Leave switch as-is but just extract branches to function calls

[weswigham]

Just to see if this alone has a perf diff.

[weswigham]

@typescript-bot perf test this faster

[typescript-bot]

Heya @weswigham, I've started to run the abridged perf test suite on this PR at e9d86d9. You can monitor the build here.

Update: The results are in!

[typescript-bot]

@weswigham
The results of the perf run you requested are in!

Here they are:

Comparison Report - main..50245

Metric	main	50245	Delta	Best	Worst
Angular - node (v14.15.1, x64)
Memory used	336,247k (± 0.01%)	336,443k (± 0.01%)	+197k (+ 0.06%)	336,383k	336,504k
Parse Time	2.06s (± 0.31%)	2.05s (± 0.43%)	-0.00s (- 0.19%)	2.04s	2.08s
Bind Time	0.89s (± 0.41%)	0.84s (± 0.59%)	🟩-0.05s (- 5.59%)	0.84s	0.86s
Check Time	5.82s (± 0.32%)	5.81s (± 0.54%)	-0.01s (- 0.15%)	5.75s	5.91s
Emit Time	6.36s (± 0.41%)	6.40s (± 0.64%)	+0.04s (+ 0.60%)	6.32s	6.50s
Total Time	15.13s (± 0.25%)	15.11s (± 0.37%)	-0.02s (- 0.15%)	15.01s	15.28s
Compiler-Unions - node (v14.15.1, x64)
Memory used	191,680k (± 0.12%)	191,857k (± 0.11%)	+178k (+ 0.09%)	190,997k	192,027k
Parse Time	0.85s (± 0.61%)	0.85s (± 0.61%)	+0.00s (+ 0.24%)	0.84s	0.86s
Bind Time	0.57s (± 1.36%)	0.52s (± 1.00%)	🟩-0.05s (- 8.76%)	0.51s	0.53s
Check Time	6.67s (± 0.65%)	6.63s (± 0.80%)	-0.04s (- 0.55%)	6.53s	6.79s
Emit Time	2.49s (± 1.06%)	2.49s (± 0.62%)	-0.00s (- 0.04%)	2.46s	2.53s
Total Time	10.58s (± 0.56%)	10.50s (± 0.56%)	-0.08s (- 0.80%)	10.38s	10.68s
Monaco - node (v14.15.1, x64)
Memory used	325,744k (± 0.00%)	325,908k (± 0.01%)	+164k (+ 0.05%)	325,834k	325,952k
Parse Time	1.58s (± 0.67%)	1.57s (± 0.71%)	-0.01s (- 0.57%)	1.55s	1.60s
Bind Time	0.78s (± 1.19%)	0.75s (± 0.40%)	🟩-0.03s (- 3.34%)	0.75s	0.76s
Check Time	5.69s (± 0.43%)	5.69s (± 0.44%)	-0.00s (- 0.04%)	5.65s	5.76s
Emit Time	3.36s (± 0.75%)	3.35s (± 0.61%)	-0.00s (- 0.00%)	3.31s	3.42s
Total Time	11.40s (± 0.45%)	11.37s (± 0.33%)	-0.04s (- 0.33%)	11.29s	11.47s
TFS - node (v14.15.1, x64)
Memory used	288,908k (± 0.01%)	289,069k (± 0.01%)	+161k (+ 0.06%)	289,022k	289,107k
Parse Time	1.35s (± 1.45%)	1.35s (± 1.56%)	+0.00s (+ 0.37%)	1.30s	1.41s
Bind Time	0.74s (± 1.35%)	0.71s (± 0.84%)	🟩-0.04s (- 5.11%)	0.69s	0.72s
Check Time	5.35s (± 0.44%)	5.34s (± 0.64%)	-0.01s (- 0.15%)	5.29s	5.43s
Emit Time	3.57s (± 1.88%)	3.66s (± 0.39%)	+0.08s (+ 2.29%)	3.63s	3.68s
Total Time	11.01s (± 0.66%)	11.05s (± 0.27%)	+0.04s (+ 0.35%)	10.99s	11.13s
material-ui - node (v14.15.1, x64)
Memory used	446,736k (± 0.07%)	447,100k (± 0.01%)	+364k (+ 0.08%)	447,033k	447,191k
Parse Time	1.87s (± 0.43%)	1.87s (± 0.69%)	-0.00s (- 0.11%)	1.85s	1.90s
Bind Time	0.72s (± 0.80%)	0.64s (± 0.87%)	🟩-0.08s (-11.20%)	0.63s	0.66s
Check Time	13.20s (± 0.72%)	13.18s (± 0.73%)	-0.02s (- 0.17%)	12.98s	13.40s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	15.80s (± 0.64%)	15.69s (± 0.61%)	-0.11s (- 0.68%)	15.50s	15.92s
xstate - node (v14.15.1, x64)
Memory used	541,914k (± 0.00%)	542,530k (± 0.00%)	+616k (+ 0.11%)	542,472k	542,579k
Parse Time	2.60s (± 0.43%)	2.60s (± 0.46%)	-0.00s (- 0.08%)	2.58s	2.63s
Bind Time	1.15s (± 0.98%)	1.05s (± 0.97%)	🟩-0.10s (- 8.86%)	1.04s	1.08s
Check Time	1.55s (± 0.47%)	1.55s (± 0.65%)	+0.00s (+ 0.13%)	1.54s	1.58s
Emit Time	0.07s (± 4.95%)	0.07s (± 0.00%)	🟩-0.01s (- 6.67%)	0.07s	0.07s
Total Time	5.38s (± 0.34%)	5.28s (± 0.37%)	-0.10s (- 1.82%)	5.24s	5.34s

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-210-generic
Architecture	x64
Available Memory	16 GB
Available Memory	15 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

• node (v14.15.1, x64)

Scenarios

• Angular - node (v14.15.1, x64)
• Compiler-Unions - node (v14.15.1, x64)
• Monaco - node (v14.15.1, x64)
• TFS - node (v14.15.1, x64)
• material-ui - node (v14.15.1, x64)
• xstate - node (v14.15.1, x64)

Benchmark	Name	Iterations
Current	50245	10
Baseline	main	10

Developer Information:

Download Benchmark

[weswigham]

@DanielRosenwasser good news! The perf improvements aren't from the switch-case change, and I'm not going crazy reading the v8 source code, unable to figure out why the switch was deoptimized (when, in fact, it wasn't)! Just extracting the various cases into individual functions looks to be most if not all of the performance improvement. So it looks like it's not the switch that's an issue, but rather the length and polymorphism of the function itself.

[weswigham]

@typescript-bot perf test this

For LS numbers for this, too~

[typescript-bot]

Heya @weswigham, I've started to run the perf test suite on this PR at e9d86d9. You can monitor the build here.

Update: The results are in!

[typescript-bot]

@weswigham
The results of the perf run you requested are in!

Here they are:

Compiler

Comparison Report - main..50245

Metric	main	50245	Delta	Best	Worst
Angular - node (v10.16.3, x64)
Memory used	360,482k (± 0.02%)	360,727k (± 0.02%)	+245k (+ 0.07%)	360,600k	360,845k
Parse Time	2.10s (± 0.39%)	2.11s (± 0.59%)	+0.01s (+ 0.48%)	2.09s	2.15s
Bind Time	0.90s (± 1.06%)	0.84s (± 0.69%)	🟩-0.05s (- 5.92%)	0.83s	0.86s
Check Time	6.03s (± 0.44%)	6.01s (± 0.51%)	-0.02s (- 0.38%)	5.93s	6.06s
Emit Time	6.17s (± 0.95%)	6.18s (± 0.72%)	+0.01s (+ 0.23%)	6.08s	6.26s
Total Time	15.21s (± 0.54%)	15.15s (± 0.45%)	-0.06s (- 0.39%)	14.97s	15.27s
Compiler-Unions - node (v10.16.3, x64)
Memory used	205,599k (± 0.04%)	205,751k (± 0.03%)	+152k (+ 0.07%)	205,612k	205,932k
Parse Time	0.83s (± 0.93%)	0.83s (± 0.40%)	-0.00s (- 0.12%)	0.82s	0.84s
Bind Time	0.52s (± 1.56%)	0.50s (± 0.96%)	🟩-0.03s (- 4.97%)	0.49s	0.51s
Check Time	7.09s (± 0.54%)	7.03s (± 0.44%)	-0.06s (- 0.83%)	6.94s	7.10s
Emit Time	2.51s (± 0.91%)	2.54s (± 0.75%)	+0.03s (+ 1.24%)	2.51s	2.58s
Total Time	10.95s (± 0.55%)	10.89s (± 0.39%)	-0.06s (- 0.51%)	10.78s	10.98s
Monaco - node (v10.16.3, x64)
Memory used	344,006k (± 0.02%)	344,152k (± 0.01%)	+146k (+ 0.04%)	344,097k	344,273k
Parse Time	1.60s (± 0.36%)	1.60s (± 0.73%)	-0.00s (- 0.06%)	1.56s	1.62s
Bind Time	0.75s (± 0.48%)	0.73s (± 0.96%)	🟩-0.03s (- 3.32%)	0.72s	0.75s
Check Time	5.98s (± 0.53%)	5.98s (± 0.95%)	-0.00s (- 0.02%)	5.80s	6.06s
Emit Time	3.25s (± 0.70%)	3.29s (± 1.06%)	+0.04s (+ 1.26%)	3.20s	3.36s
Total Time	11.59s (± 0.40%)	11.60s (± 0.47%)	+0.02s (+ 0.13%)	11.47s	11.73s
TFS - node (v10.16.3, x64)
Memory used	305,299k (± 0.03%)	305,443k (± 0.03%)	+144k (+ 0.05%)	305,209k	305,652k
Parse Time	1.29s (± 0.63%)	1.28s (± 0.46%)	-0.00s (- 0.23%)	1.27s	1.30s
Bind Time	0.72s (± 0.66%)	0.70s (± 0.97%)	-0.01s (- 1.81%)	0.69s	0.72s
Check Time	5.41s (± 0.35%)	5.45s (± 0.50%)	+0.04s (+ 0.68%)	5.40s	5.50s
Emit Time	3.43s (± 1.28%)	3.53s (± 1.68%)	+0.10s (+ 3.00%)	3.41s	3.67s
Total Time	10.85s (± 0.50%)	10.97s (± 0.72%)	+0.12s (+ 1.10%)	10.83s	11.15s
material-ui - node (v10.16.3, x64)
Memory used	469,616k (± 0.01%)	469,779k (± 0.02%)	+163k (+ 0.03%)	469,582k	469,956k
Parse Time	1.83s (± 0.44%)	1.83s (± 0.82%)	+0.00s (+ 0.05%)	1.81s	1.86s
Bind Time	0.69s (± 1.60%)	0.63s (± 1.58%)	🟩-0.06s (- 8.26%)	0.61s	0.65s
Check Time	14.55s (± 0.66%)	14.60s (± 0.97%)	+0.05s (+ 0.37%)	14.39s	15.00s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	17.07s (± 0.56%)	17.07s (± 0.87%)	-0.00s (- 0.02%)	16.84s	17.48s
xstate - node (v10.16.3, x64)
Memory used	578,760k (± 0.02%)	579,382k (± 0.01%)	+622k (+ 0.11%)	579,255k	579,527k
Parse Time	2.60s (± 0.41%)	2.60s (± 0.23%)	+0.01s (+ 0.31%)	2.59s	2.61s
Bind Time	1.02s (± 0.99%)	0.94s (± 0.63%)	🟩-0.08s (- 7.87%)	0.93s	0.95s
Check Time	1.57s (± 0.56%)	1.57s (± 0.67%)	+0.01s (+ 0.38%)	1.54s	1.59s
Emit Time	0.07s (± 3.14%)	0.07s (± 0.00%)	-0.00s (- 1.41%)	0.07s	0.07s
Total Time	5.25s (± 0.34%)	5.18s (± 0.24%)	-0.07s (- 1.26%)	5.14s	5.20s
Angular - node (v12.1.0, x64)
Memory used	337,877k (± 0.08%)	338,315k (± 0.02%)	+438k (+ 0.13%)	338,174k	338,428k
Parse Time	2.08s (± 0.45%)	2.08s (± 0.44%)	+0.00s (+ 0.14%)	2.06s	2.10s
Bind Time	0.85s (± 0.58%)	0.82s (± 0.61%)	🟩-0.04s (- 4.68%)	0.81s	0.83s
Check Time	5.85s (± 0.81%)	5.82s (± 0.48%)	-0.03s (- 0.53%)	5.78s	5.91s
Emit Time	6.44s (± 0.96%)	6.40s (± 0.64%)	-0.05s (- 0.73%)	6.31s	6.53s
Total Time	15.23s (± 0.57%)	15.12s (± 0.35%)	-0.12s (- 0.76%)	15.02s	15.23s
Compiler-Unions - node (v12.1.0, x64)
Memory used	193,244k (± 0.02%)	192,941k (± 0.31%)	-303k (- 0.16%)	190,685k	193,507k
Parse Time	0.83s (± 0.72%)	0.82s (± 0.58%)	-0.00s (- 0.36%)	0.81s	0.83s
Bind Time	0.55s (± 0.94%)	0.51s (± 0.99%)	🟩-0.05s (- 8.35%)	0.50s	0.52s
Check Time	6.64s (± 0.60%)	6.63s (± 0.46%)	-0.00s (- 0.08%)	6.58s	6.71s
Emit Time	2.54s (± 1.44%)	2.54s (± 0.99%)	-0.00s (- 0.08%)	2.49s	2.59s
Total Time	10.56s (± 0.33%)	10.50s (± 0.35%)	-0.06s (- 0.53%)	10.43s	10.60s
Monaco - node (v12.1.0, x64)
Memory used	326,952k (± 0.02%)	327,088k (± 0.01%)	+136k (+ 0.04%)	326,996k	327,203k
Parse Time	1.57s (± 0.74%)	1.58s (± 0.74%)	+0.00s (+ 0.32%)	1.54s	1.60s
Bind Time	0.74s (± 0.70%)	0.72s (± 0.82%)	-0.02s (- 2.03%)	0.71s	0.74s
Check Time	5.81s (± 0.46%)	5.83s (± 0.57%)	+0.02s (+ 0.28%)	5.77s	5.92s
Emit Time	3.30s (± 0.93%)	3.30s (± 0.72%)	-0.01s (- 0.21%)	3.26s	3.37s
Total Time	11.43s (± 0.41%)	11.43s (± 0.36%)	-0.00s (- 0.03%)	11.35s	11.54s
TFS - node (v12.1.0, x64)
Memory used	289,789k (± 0.06%)	290,035k (± 0.03%)	+246k (+ 0.08%)	289,923k	290,248k
Parse Time	1.29s (± 1.18%)	1.30s (± 0.83%)	+0.00s (+ 0.39%)	1.28s	1.33s
Bind Time	0.72s (± 0.93%)	0.68s (± 1.21%)	🟩-0.03s (- 4.60%)	0.67s	0.71s
Check Time	5.38s (± 0.50%)	5.36s (± 0.33%)	-0.02s (- 0.33%)	5.32s	5.40s
Emit Time	3.53s (± 0.62%)	3.51s (± 1.06%)	-0.02s (- 0.42%)	3.44s	3.61s
Total Time	10.92s (± 0.37%)	10.86s (± 0.39%)	-0.06s (- 0.55%)	10.73s	10.97s
material-ui - node (v12.1.0, x64)
Memory used	448,726k (± 0.01%)	448,824k (± 0.06%)	+99k (+ 0.02%)	447,695k	449,108k
Parse Time	1.82s (± 0.55%)	1.82s (± 0.66%)	+0.00s (+ 0.05%)	1.81s	1.87s
Bind Time	0.67s (± 0.70%)	0.60s (± 0.82%)	🟩-0.07s (- 9.85%)	0.60s	0.62s
Check Time	13.04s (± 0.73%)	13.10s (± 0.64%)	+0.06s (+ 0.45%)	12.94s	13.32s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	15.54s (± 0.65%)	15.53s (± 0.57%)	-0.00s (- 0.03%)	15.37s	15.75s
xstate - node (v12.1.0, x64)
Memory used	547,481k (± 1.32%)	544,834k (± 0.02%)	-2,647k (- 0.48%)	544,622k	545,234k
Parse Time	2.54s (± 0.39%)	2.55s (± 0.54%)	+0.01s (+ 0.28%)	2.52s	2.58s
Bind Time	1.03s (± 1.37%)	0.93s (± 1.58%)	🟩-0.11s (-10.45%)	0.91s	0.98s
Check Time	1.51s (± 0.60%)	1.52s (± 0.39%)	+0.01s (+ 0.33%)	1.50s	1.53s
Emit Time	0.07s (± 0.00%)	0.07s (± 0.00%)	0.00s ( 0.00%)	0.07s	0.07s
Total Time	5.16s (± 0.43%)	5.06s (± 0.45%)	-0.10s (- 1.86%)	5.01s	5.12s
Angular - node (v14.15.1, x64)
Memory used	336,295k (± 0.01%)	336,439k (± 0.01%)	+145k (+ 0.04%)	336,390k	336,488k
Parse Time	2.07s (± 0.70%)	2.06s (± 0.61%)	-0.00s (- 0.24%)	2.04s	2.09s
Bind Time	0.89s (± 0.50%)	0.85s (± 0.56%)	🟩-0.04s (- 4.62%)	0.84s	0.86s
Check Time	5.85s (± 0.25%)	5.83s (± 0.64%)	-0.02s (- 0.31%)	5.75s	5.93s
Emit Time	6.36s (± 0.58%)	6.41s (± 1.06%)	+0.05s (+ 0.74%)	6.27s	6.54s
Total Time	15.16s (± 0.35%)	15.14s (± 0.65%)	-0.01s (- 0.09%)	14.91s	15.38s
Compiler-Unions - node (v14.15.1, x64)
Memory used	191,835k (± 0.01%)	191,985k (± 0.02%)	+150k (+ 0.08%)	191,924k	192,083k
Parse Time	0.85s (± 0.65%)	0.85s (± 0.52%)	0.00s ( 0.00%)	0.84s	0.86s
Bind Time	0.57s (± 0.63%)	0.52s (± 0.43%)	🟩-0.06s (- 9.58%)	0.51s	0.52s
Check Time	6.67s (± 0.61%)	6.65s (± 0.81%)	-0.02s (- 0.36%)	6.51s	6.74s
Emit Time	2.50s (± 1.44%)	2.49s (± 0.65%)	-0.01s (- 0.48%)	2.46s	2.53s
Total Time	10.60s (± 0.40%)	10.51s (± 0.56%)	-0.09s (- 0.89%)	10.38s	10.61s
Monaco - node (v14.15.1, x64)
Memory used	325,761k (± 0.01%)	325,901k (± 0.01%)	+139k (+ 0.04%)	325,843k	325,929k
Parse Time	1.58s (± 0.42%)	1.58s (± 0.89%)	+0.00s (+ 0.19%)	1.56s	1.61s
Bind Time	0.78s (± 0.67%)	0.75s (± 0.49%)	🟩-0.02s (- 3.08%)	0.75s	0.76s
Check Time	5.71s (± 0.39%)	5.67s (± 0.35%)	-0.04s (- 0.65%)	5.63s	5.71s
Emit Time	3.38s (± 0.80%)	3.34s (± 0.48%)	-0.04s (- 1.24%)	3.30s	3.37s
Total Time	11.44s (± 0.24%)	11.35s (± 0.31%)	-0.10s (- 0.85%)	11.26s	11.42s
TFS - node (v14.15.1, x64)
Memory used	288,887k (± 0.01%)	289,088k (± 0.01%)	+202k (+ 0.07%)	289,047k	289,132k
Parse Time	1.34s (± 2.18%)	1.33s (± 0.98%)	-0.01s (- 1.04%)	1.29s	1.35s
Bind Time	0.74s (± 3.55%)	0.73s (± 4.38%)	-0.02s (- 2.42%)	0.69s	0.82s
Check Time	5.37s (± 0.39%)	5.32s (± 0.35%)	-0.05s (- 0.84%)	5.29s	5.37s
Emit Time	3.58s (± 2.21%)	3.62s (± 1.56%)	+0.04s (+ 1.12%)	3.46s	3.68s
Total Time	11.04s (± 0.92%)	11.00s (± 0.53%)	-0.04s (- 0.34%)	10.83s	11.11s
material-ui - node (v14.15.1, x64)
Memory used	446,924k (± 0.01%)	447,092k (± 0.01%)	+168k (+ 0.04%)	446,998k	447,170k
Parse Time	1.87s (± 0.46%)	1.87s (± 0.57%)	+0.00s (+ 0.05%)	1.85s	1.89s
Bind Time	0.72s (± 0.68%)	0.64s (± 0.53%)	🟩-0.08s (-11.19%)	0.64s	0.65s
Check Time	13.15s (± 0.49%)	13.20s (± 0.54%)	+0.05s (+ 0.37%)	13.01s	13.33s
Emit Time	0.00s (± 0.00%)	0.00s (± 0.00%)	0.00s ( NaN%)	0.00s	0.00s
Total Time	15.74s (± 0.46%)	15.71s (± 0.45%)	-0.03s (- 0.21%)	15.53s	15.87s
xstate - node (v14.15.1, x64)
Memory used	541,989k (± 0.00%)	542,531k (± 0.00%)	+542k (+ 0.10%)	542,478k	542,578k
Parse Time	2.60s (± 0.32%)	2.61s (± 0.48%)	+0.01s (+ 0.42%)	2.58s	2.63s
Bind Time	1.16s (± 0.70%)	1.05s (± 0.55%)	🟩-0.11s (- 9.74%)	1.04s	1.06s
Check Time	1.55s (± 0.52%)	1.56s (± 0.45%)	+0.01s (+ 0.71%)	1.55s	1.58s
Emit Time	0.07s (± 3.14%)	0.07s (± 0.00%)	-0.00s (- 1.41%)	0.07s	0.07s
Total Time	5.38s (± 0.16%)	5.28s (± 0.29%)	-0.10s (- 1.80%)	5.23s	5.30s

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-210-generic
Architecture	x64
Available Memory	16 GB
Available Memory	15 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

• node (v10.16.3, x64)
• node (v12.1.0, x64)
• node (v14.15.1, x64)

Scenarios

• Angular - node (v10.16.3, x64)
• Angular - node (v12.1.0, x64)
• Angular - node (v14.15.1, x64)
• Compiler-Unions - node (v10.16.3, x64)
• Compiler-Unions - node (v12.1.0, x64)
• Compiler-Unions - node (v14.15.1, x64)
• Monaco - node (v10.16.3, x64)
• Monaco - node (v12.1.0, x64)
• Monaco - node (v14.15.1, x64)
• TFS - node (v10.16.3, x64)
• TFS - node (v12.1.0, x64)
• TFS - node (v14.15.1, x64)
• material-ui - node (v10.16.3, x64)
• material-ui - node (v12.1.0, x64)
• material-ui - node (v14.15.1, x64)
• xstate - node (v10.16.3, x64)
• xstate - node (v12.1.0, x64)
• xstate - node (v14.15.1, x64)

Benchmark	Name	Iterations
Current	50245	10
Baseline	main	10

TSServer

Comparison Report - main..50245

Metric	main	50245	Delta	Best	Worst
Compiler-UnionsTSServer - node (v10.16.3, x64)
Req 1 - updateOpen	1,453ms (± 0.37%)	1,429ms (± 0.40%)	-24ms (- 1.67%)	1,417ms	1,442ms
Req 2 - geterr	3,617ms (± 0.32%)	3,584ms (± 0.49%)	-34ms (- 0.93%)	3,541ms	3,626ms
Req 3 - references	276ms (± 0.69%)	232ms (± 0.53%)	🟩-45ms (-16.11%)	229ms	235ms
Req 4 - navto	231ms (± 0.76%)	174ms (± 1.37%)	🟩-57ms (-24.85%)	167ms	179ms
Req 5 - completionInfo count	1,355 (± 0.00%)	1,355 (± 0.00%)	0 ( 0.00%)	1,355	1,355
Req 5 - completionInfo	64ms (± 3.30%)	62ms (± 2.83%)	🟩-2ms (- 3.59%)	59ms	67ms
CompilerTSServer - node (v10.16.3, x64)
Req 1 - updateOpen	1,552ms (± 0.59%)	1,524ms (± 0.66%)	-28ms (- 1.79%)	1,498ms	1,548ms
Req 2 - geterr	2,265ms (± 0.46%)	2,227ms (± 0.45%)	-38ms (- 1.68%)	2,207ms	2,242ms
Req 3 - references	295ms (± 0.75%)	244ms (± 0.87%)	🟩-50ms (-17.11%)	240ms	249ms
Req 4 - navto	237ms (± 2.09%)	188ms (± 1.01%)	🟩-49ms (-20.51%)	183ms	191ms
Req 5 - completionInfo count	1,517 (± 0.00%)	1,517 (± 0.00%)	0 ( 0.00%)	1,517	1,517
Req 5 - completionInfo	66ms (± 2.97%)	69ms (± 0.75%)	+4ms (+ 5.50%)	68ms	70ms
xstateTSServer - node (v10.16.3, x64)
Req 1 - updateOpen	2,175ms (± 0.58%)	2,104ms (± 0.53%)	🟩-71ms (- 3.25%)	2,083ms	2,134ms
Req 2 - geterr	776ms (± 0.42%)	778ms (± 0.75%)	+2ms (+ 0.23%)	766ms	793ms
Req 3 - references	97ms (± 1.16%)	98ms (± 3.89%)	+1ms (+ 1.14%)	95ms	113ms
Req 4 - navto	256ms (± 0.89%)	242ms (± 1.10%)	🟩-14ms (- 5.36%)	236ms	248ms
Req 5 - completionInfo count	3,244 (± 0.00%)	3,244 (± 0.00%)	0 ( 0.00%)	3,244	3,244
Req 5 - completionInfo	274ms (± 1.49%)	271ms (± 1.11%)	-3ms (- 1.10%)	263ms	275ms
Compiler-UnionsTSServer - node (v12.1.0, x64)
Req 1 - updateOpen	1,485ms (± 0.52%)	1,438ms (± 0.55%)	🟩-47ms (- 3.13%)	1,420ms	1,456ms
Req 2 - geterr	3,412ms (± 0.60%)	3,351ms (± 0.47%)	-61ms (- 1.78%)	3,309ms	3,371ms
Req 3 - references	262ms (± 0.76%)	220ms (± 0.68%)	🟩-42ms (-15.94%)	217ms	223ms
Req 4 - navto	206ms (± 0.69%)	161ms (± 0.91%)	🟩-45ms (-21.90%)	157ms	163ms
Req 5 - completionInfo count	1,355 (± 0.00%)	1,355 (± 0.00%)	0 ( 0.00%)	1,355	1,355
Req 5 - completionInfo	72ms (±15.95%)	59ms (±10.30%)	🟩-13ms (-17.78%)	54ms	83ms
CompilerTSServer - node (v12.1.0, x64)
Req 1 - updateOpen	1,566ms (± 0.46%)	1,529ms (± 0.46%)	-38ms (- 2.41%)	1,512ms	1,545ms
Req 2 - geterr	2,201ms (± 0.43%)	2,163ms (± 0.48%)	-38ms (- 1.72%)	2,145ms	2,195ms
Req 3 - references	272ms (± 0.97%)	236ms (± 0.87%)	🟩-37ms (-13.51%)	231ms	240ms
Req 4 - navto	217ms (± 1.96%)	175ms (± 1.31%)	🟩-42ms (-19.44%)	171ms	181ms
Req 5 - completionInfo count	1,517 (± 0.00%)	1,517 (± 0.00%)	0 ( 0.00%)	1,517	1,517
Req 5 - completionInfo	60ms (± 3.64%)	62ms (± 4.89%)	+2ms (+ 3.49%)	55ms	66ms
xstateTSServer - node (v12.1.0, x64)
Req 1 - updateOpen	2,098ms (± 0.22%)	2,061ms (± 0.63%)	-37ms (- 1.77%)	2,042ms	2,100ms
Req 2 - geterr	762ms (± 0.57%)	767ms (± 0.72%)	+4ms (+ 0.56%)	759ms	784ms
Req 3 - references	65ms (± 1.75%)	66ms (± 1.28%)	+1ms (+ 1.38%)	64ms	68ms
Req 4 - navto	243ms (± 0.84%)	230ms (± 1.49%)	🟩-12ms (- 5.03%)	225ms	241ms
Req 5 - completionInfo count	3,244 (± 0.00%)	3,244 (± 0.00%)	0 ( 0.00%)	3,244	3,244
Req 5 - completionInfo	264ms (± 1.21%)	265ms (± 1.81%)	+1ms (+ 0.49%)	257ms	280ms
Compiler-UnionsTSServer - node (v14.15.1, x64)
Req 1 - updateOpen	1,529ms (± 0.41%)	1,477ms (± 0.60%)	🟩-52ms (- 3.39%)	1,455ms	1,498ms
Req 2 - geterr	3,542ms (± 0.33%)	3,523ms (± 0.47%)	-19ms (- 0.52%)	3,493ms	3,570ms
Req 3 - references	277ms (± 0.36%)	231ms (± 0.70%)	🟩-45ms (-16.41%)	229ms	237ms
Req 4 - navto	217ms (± 0.48%)	170ms (± 1.00%)	🟩-47ms (-21.72%)	167ms	175ms
Req 5 - completionInfo count	1,355 (± 0.00%)	1,355 (± 0.00%)	0 ( 0.00%)	1,355	1,355
Req 5 - completionInfo	57ms (± 5.37%)	58ms (± 5.54%)	+0ms (+ 0.35%)	55ms	66ms
CompilerTSServer - node (v14.15.1, x64)
Req 1 - updateOpen	1,603ms (± 0.56%)	1,557ms (± 0.83%)	-47ms (- 2.91%)	1,535ms	1,596ms
Req 2 - geterr	2,334ms (± 0.34%)	2,304ms (± 0.48%)	-30ms (- 1.27%)	2,279ms	2,323ms
Req 3 - references	284ms (± 0.48%)	243ms (± 0.56%)	🟩-41ms (-14.56%)	240ms	246ms
Req 4 - navto	228ms (± 0.33%)	180ms (± 0.41%)	🟩-48ms (-20.92%)	178ms	182ms
Req 5 - completionInfo count	1,517 (± 0.00%)	1,517 (± 0.00%)	0 ( 0.00%)	1,517	1,517
Req 5 - completionInfo	53ms (± 0.98%)	53ms (± 1.05%)	-0ms (- 0.56%)	52ms	54ms
xstateTSServer - node (v14.15.1, x64)
Req 1 - updateOpen	2,226ms (± 0.51%)	2,176ms (± 0.40%)	-49ms (- 2.21%)	2,160ms	2,193ms
Req 2 - geterr	780ms (± 0.39%)	782ms (± 0.39%)	+2ms (+ 0.26%)	775ms	789ms
Req 3 - references	64ms (± 0.73%)	65ms (± 1.30%)	+1ms (+ 1.72%)	64ms	68ms
Req 4 - navto	249ms (± 0.82%)	236ms (± 0.82%)	🟩-14ms (- 5.42%)	230ms	239ms
Req 5 - completionInfo count	3,244 (± 0.00%)	3,244 (± 0.00%)	0 ( 0.00%)	3,244	3,244
Req 5 - completionInfo	267ms (± 0.40%)	268ms (± 0.77%)	+0ms (+ 0.04%)	262ms	271ms

System

Machine Name	ts-ci-ubuntu
Platform	linux 4.4.0-210-generic
Architecture	x64
Available Memory	16 GB
Available Memory	15 GB
CPUs	4 × Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

Hosts

• node (v10.16.3, x64)
• node (v12.1.0, x64)
• node (v14.15.1, x64)

Scenarios

• Compiler-UnionsTSServer - node (v10.16.3, x64)
• Compiler-UnionsTSServer - node (v12.1.0, x64)
• Compiler-UnionsTSServer - node (v14.15.1, x64)
• CompilerTSServer - node (v10.16.3, x64)
• CompilerTSServer - node (v12.1.0, x64)
• CompilerTSServer - node (v14.15.1, x64)
• xstateTSServer - node (v10.16.3, x64)
• xstateTSServer - node (v12.1.0, x64)
• xstateTSServer - node (v14.15.1, x64)

Benchmark	Name	Iterations
Current	50245	10
Baseline	main	10

Developer Information:

Download Benchmark

[jakebailey]

I do like the improved safety of this one over #50225.

Would the perf be identical if these functions were instead declared at the bottom of forEachChild? That way, nobody could actually try and call them.

(This is probably very moot post-modules, as this whole thing could be its own file that doesn't export them.)

[rbuckton]

I wonder if V8 is using a jump table for the switch now that it has no fall-through cases.

Would the perf be identical if these functions were instead declared at the bottom of forEachChild? That way, nobody could actually try and call them.

These functions don't need to be exported from ts either and it might make sense to just move forEachChild et all to its own file anyways.

[weswigham]

I ultimately like @DanielRosenwasser 's PR more, simply because it is yet more performant, but it looks like the perf improvement is correlated with the instruction length of the function and not the presence or lack thereof of the switch, which is what I wanted to confirm with this.

[weswigham]

I wonder if V8 is using a jump table for the switch now that it has no fall-through cases.

Based on the conditions for switch optimization I read in the v8 sources, both before this PR and with this PR, the switch should be optimized to a jump table. For an interpreted function, you get a jump table so long as you have a minimum number of branches and cover at least 33% of the range of inputs (measured as the difference between the min and max case values). On x64, for a compiled function, there's a somewhat complex space/time tradeoff heuristic where it falls back to a binary search, but it weights the time metric more, and for anything with a somewhat densely filled out list of cases, should prefer the jump table. There's links to the relevant v8 sources in our internal discussions, if you're curious about the exact heuristic. AFAIK, the 128 case limit mentioned in the recently-trended blog post about a perf problem from 2013 no longer seems to exist - on x64, the max case count for a jump table is 2 << 16. (And fall throughs don't seem to affect it in any way - they count as a case same as any other)