Performance of coldTask and cancellableTask

[TheAngryByrd]

I've got benchmarks from FSharp.Core working on this codebase.

With function fun () ->/fun ct -> at beginning of Run/Dynamic coldTask cancellableTask

With function at beginning of Run/Dynamic

Method	Categories	Mean	Error	StdDev	Gen 0	Gen 1	Allocated
ManyWriteFile_ply	ManyWriteFile	3.128 ms	0.1152 ms	0.3362 ms	-	-	10 KB
ManyWriteFile_async	ManyWriteFile	3.549 ms	0.0713 ms	0.2035 ms	31.2500	7.8125	292 KB
ManyWriteFile_task	ManyWriteFile	3.199 ms	0.0928 ms	0.2707 ms	-	-	8 KB
ManyWriteFile_coldTask	ManyWriteFile	3.716 ms	0.1606 ms	0.4735 ms	23.4375	7.8125	219 KB
ManyWriteFile_cancellableTask	ManyWriteFile	3.462 ms	0.1497 ms	0.4391 ms	15.6250	7.8125	134 KB
NonAsyncBinds_ply	NonAsyncBinds	18.858 ms	0.3729 ms	0.8862 ms	9468.7500	-	77,344 KB
NonAsyncBinds_async	NonAsyncBinds	1,401.882 ms	53.8624 ms	158.8146 ms	30000.0000	-	248,438 KB
NonAsyncBinds_task	NonAsyncBinds	16.959 ms	0.3377 ms	0.7759 ms	9468.7500	-	77,344 KB
NonAsyncBinds_coldTask	NonAsyncBinds	51.517 ms	1.0237 ms	2.9039 ms	26400.0000	-	216,406 KB
NonAsyncBinds_cancellationTask	NonAsyncBinds	82.281 ms	1.6268 ms	2.2805 ms	39571.4286	-	324,219 KB
AsyncBinds_ply	AsyncBinds	24.414 ms	0.4566 ms	0.8233 ms	62.5000	-	656 KB
AsyncBinds_async	AsyncBinds	115.684 ms	2.5590 ms	7.4647 ms	1000.0000	-	8,375 KB
AsyncBinds_task	AsyncBinds	22.444 ms	0.4395 ms	0.7812 ms	-	-	188 KB
AsyncBinds_coldTask	AsyncBinds	23.649 ms	0.4698 ms	0.9382 ms	218.7500	-	1,922 KB
AsyncBinds_cancellableTask	AsyncBinds	23.748 ms	0.4737 ms	0.9569 ms	218.7500	-	1,930 KB

With function near end of Run/Dynamic

Method	Categories	Mean	Error	StdDev	Median	Gen 0	Gen 1	Allocated
ManyWriteFile_ply	ManyWriteFile	2.749 ms	0.0534 ms	0.0907 ms	2.730 ms	-	-	10 KB
ManyWriteFile_async	ManyWriteFile	2.977 ms	0.0593 ms	0.0906 ms	2.968 ms	35.1563	11.7188	292 KB
ManyWriteFile_task	ManyWriteFile	2.761 ms	0.0549 ms	0.1095 ms	2.769 ms	-	-	8 KB
ManyWriteFile_coldTask	ManyWriteFile	2.797 ms	0.0547 ms	0.0958 ms	2.805 ms	-	-	8 KB
ManyWriteFile_cancellableTask	ManyWriteFile	2.781 ms	0.0548 ms	0.1042 ms	2.752 ms	-	-	8 KB
NonAsyncBinds_ply	NonAsyncBinds	18.027 ms	0.3547 ms	0.3795 ms	17.964 ms	9468.7500	-	77,344 KB
NonAsyncBinds_async	NonAsyncBinds	1,268.306 ms	46.0299 ms	132.8067 ms	1,219.354 ms	30000.0000	-	248,438 KB
NonAsyncBinds_task	NonAsyncBinds	14.717 ms	0.1840 ms	0.1537 ms	14.714 ms	9468.7500	-	77,344 KB
NonAsyncBinds_coldTask	NonAsyncBinds	27.717 ms	0.5509 ms	1.3820 ms	28.139 ms	11562.5000	-	94,531 KB
NonAsyncBinds_cancellationTask	NonAsyncBinds	24.367 ms	0.2168 ms	0.1810 ms	24.439 ms	11656.2500	-	95,313 KB
AsyncBinds_ply	AsyncBinds	23.127 ms	0.3770 ms	0.3342 ms	23.149 ms	62.5000	-	656 KB
AsyncBinds_async	AsyncBinds	110.963 ms	2.1657 ms	4.7080 ms	109.955 ms	1000.0000	-	8,375 KB
AsyncBinds_task	AsyncBinds	22.727 ms	0.4370 ms	0.9122 ms	22.564 ms	-	-	188 KB
AsyncBinds_coldTask	AsyncBinds	21.655 ms	0.4086 ms	0.4013 ms	21.704 ms	31.2500	-	328 KB
AsyncBinds_cancellableTask	AsyncBinds	22.558 ms	0.4411 ms	0.4126 ms	22.610 ms	31.2500	-	344 KB

There's some considerable improvements here in speed and memory by moving fun () ->/fun ct ->.

However I am getting a warning:

/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/ColdTask.fs(208,13): warning FS3511: This state machine is not statically compilable. The resumable code value(s) 'code' does not have a definition. An alternative dynamic implementation will be used, which may be slower. Consider adjusting your code to ensure this state machine is statically compilable, or else suppress this warning. [/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/IcedTasks.fsproj]
/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/ColdTask.fs(257,13): warning FS3511: This state machine is not statically compilable. The resumable code value(s) 'code' does not have a definition. An alternative dynamic implementation will be used, which may be slower. Consider adjusting your code to ensure this state machine is statically compilable, or else suppress this warning. [/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/IcedTasks.fsproj]
/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/CancellableTask.fs(225,13): warning FS3511: This state machine is not statically compilable. The resumable code value(s) 'code' does not have a definition. An alternative dynamic implementation will be used, which may be slower. Consider adjusting your code to ensure this state machine is statically compilable, or else suppress this warning. [/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/IcedTasks.fsproj]
/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/CancellableTask.fs(277,13): warning FS3511: This state machine is not statically compilable. The resumable code value(s) 'code' does not have a definition. An alternative dynamic implementation will be used, which may be slower. Consider adjusting your code to ensure this state machine is statically compilable, or else suppress this warning. [/repos/public/TheAngryByrd/IcedTasks/src/IcedTasks/IcedTasks.fsproj]

---

Update: 2022/03/08

Method	Categories	Mean	Error	StdDev	Median	Ratio	RatioSD	Gen 0	Gen 1	Allocated
ManyWriteFile_CSharpTasks	ManyWriteFile	1,078.9 us	25.94 us	73.18 us	1,060.2 us	1.00	0.00	-	-	10 KB
ManyWriteFile_ply	ManyWriteFile	1,182.8 us	50.84 us	148.30 us	1,115.1 us	1.10	0.16	-	-	10 KB
ManyWriteFile_async	ManyWriteFile	1,300.5 us	21.41 us	43.73 us	1,293.1 us	1.22	0.09	35.1563	11.7188	292 KB
ManyWriteFile_task	ManyWriteFile	1,051.1 us	21.02 us	44.34 us	1,050.3 us	0.98	0.08	-	-	8 KB
ManyWriteFile_coldTask	ManyWriteFile	1,135.9 us	39.39 us	115.54 us	1,086.7 us	1.06	0.11	-	-	8 KB
ManyWriteFile_cancellableTask	ManyWriteFile	1,124.4 us	43.13 us	125.80 us	1,073.6 us	1.04	0.12	-	-	8 KB
ManyWriteFile_cancellableTask_withCancellation	ManyWriteFile	1,067.2 us	25.44 us	72.16 us	1,051.6 us	0.99	0.10	-	-	9 KB
ManyWriteFile_cancellableTask_withCancellation2	ManyWriteFile	951.3 us	18.90 us	47.06 us	938.7 us	0.89	0.07	0.9766	-	8 KB
ManyWriteFile_cancellableTask_withCancellation3	ManyWriteFile	1,109.2 us	21.85 us	51.51 us	1,105.6 us	1.03	0.08	9.7656	3.9063	79 KB
NonAsyncBinds_CSharpTasks	NonAsyncBinds	10,343.1 us	198.70 us	204.05 us	10,319.2 us	1.00	0.00	9468.7500	-	77,344 KB
NonAsyncBinds_ply	NonAsyncBinds	14,213.2 us	280.04 us	354.17 us	14,095.1 us	1.39	0.05	9468.7500	-	77,344 KB
NonAsyncBinds_async	NonAsyncBinds	833,404.7 us	14,209.76 us	13,291.82 us	830,307.9 us	80.75	2.57	30000.0000	-	248,439 KB
NonAsyncBinds_task	NonAsyncBinds	12,405.7 us	244.80 us	388.28 us	12,435.8 us	1.19	0.04	9468.7500	-	77,344 KB
NonAsyncBinds_coldTask_bindTask	NonAsyncBinds	20,537.8 us	359.23 us	413.68 us	20,457.3 us	1.99	0.07	11281.2500	-	92,188 KB
NonAsyncBinds_coldTask_bindColdTask	NonAsyncBinds	20,325.6 us	399.94 us	533.91 us	20,309.0 us	1.94	0.05	11281.2500	-	92,188 KB
NonAsyncBinds_cancellableTask_bindTask	NonAsyncBinds	21,093.6 us	416.13 us	479.22 us	21,166.3 us	2.04	0.04	11375.0000	-	92,969 KB
NonAsyncBinds_cancellableTask	NonAsyncBinds	21,430.7 us	324.82 us	287.95 us	21,404.5 us	2.08	0.05	11375.0000	-	92,969 KB
AsyncBinds_CSharpTasks	AsyncBinds	16,633.3 us	390.48 us	1,151.35 us	16,912.3 us	1.00	0.00	-	-	109 KB
AsyncBinds_ply	AsyncBinds	19,719.0 us	390.94 us	480.11 us	19,798.5 us	1.30	0.08	62.5000	-	656 KB
AsyncBinds_async	AsyncBinds	80,239.3 us	1,338.74 us	1,186.76 us	79,870.7 us	5.37	0.25	1000.0000	-	8,376 KB
AsyncBinds_task	AsyncBinds	18,808.0 us	450.99 us	1,329.76 us	18,603.0 us	1.14	0.13	15.6250	-	188 KB
AsyncBinds_coldTask_bindTask	AsyncBinds	18,126.6 us	361.36 us	983.10 us	17,961.7 us	1.10	0.09	31.2500	-	305 KB
AsyncBinds_coldTask_bindColdTask	AsyncBinds	18,207.5 us	363.97 us	608.11 us	18,177.3 us	1.18	0.06	31.2500	-	305 KB
AsyncBinds_cancellableTask_bindTask	AsyncBinds	18,366.8 us	359.93 us	527.57 us	18,456.9 us	1.21	0.07	31.2500	-	320 KB
AsyncBinds_cancellableTask_bindCancellableTask	AsyncBinds	15,207.0 us	298.83 us	377.93 us	15,213.7 us	1.01	0.05	31.2500	-	320 KB

[baronfel]

• Sharplab ColdTask fun at top
• Sharplab ColdTask fun at bottom

Biggest difference I see is that the before version of ManyWriteFile_coldTask has more local state and it ends up calling the 'dynamic' version of try/finally, whereas the after version of ManyWriteFile_coldTask takes a state machine as input and the implementation of the state machine is more unrolled. The 'after' version appears to be more correct to me - the generated code for a callsite constructs a packet with the state machine data and then sends that packet to the state machine processor.

[TheAngryByrd]

Thanks for throwing it into Sharplab and showing the state machine being generated correctly for the fun at bottom implementation. Benchmarks definitely support this.

The weird thing is, with this implementation I'm getting This state machine is not statically compilable. The resumable code value(s) 'code' does not have a definition. An alternative dynamic implementation will be used, which may be slower. Consider adjusting your code to ensure this state machine is statically compilable, or else suppress this warning. , which would make me think the opposite is happening. @dsyme do you know why this might be the case?