Await.HeadExplosion

Value Tasks

BenchmarkDotNet=v0.10.13, OS=Windows 10 Redstone 3 [1709, Fall Creators Update] (10.0.16299.309)
Intel Core i7-8550U CPU 1.80GHz (Kaby Lake R), 1 CPU, 8 logical cores and 4 physical cores
Frequency=1945315 Hz, Resolution=514.0556 ns, Timer=TSC
.NET Core SDK=2.1.103
  [Host]   : .NET Core 2.0.6 (CoreCLR 4.6.26212.01, CoreFX 4.6.26212.01), 64bit RyuJIT
  ShortRun : .NET Core 2.0.6 (CoreCLR 4.6.26212.01, CoreFX 4.6.26212.01), 64bit RyuJIT

Job=ShortRun  LaunchCount=1  TargetCount=3  
WarmupCount=3  

Method	Repeats	Mean	Error	StdDev	Scaled	ScaledSD	Gen 0	Allocated
ConsumeTask	100	874.7 ns	3,155.10 ns	178.269 ns	2.54	0.43	1.7328	7272 B
ConsumeValueTaskWrong	100	998.2 ns	1,419.13 ns	80.183 ns	2.90	0.21	-	0 B
ConsumeValueTaskProperly	100	344.9 ns	224.85 ns	12.705 ns	1.00	0.00	-	0 B
ConsumeValueTaskCrazy	100	361.3 ns	59.83 ns	3.380 ns	1.05	0.03	-	0 B
ConsumeTask	1000	10,000.4 ns	49,937.52 ns	2,821.562 ns	3.23	0.76	17.1814	72072 B
ConsumeValueTaskWrong	1000	9,508.8 ns	3,116.34 ns	176.079 ns	3.07	0.14	-	0 B
ConsumeValueTaskProperly	1000	3,103.0 ns	2,864.84 ns	161.869 ns	1.00	0.00	-	0 B
ConsumeValueTaskCrazy	1000	3,283.8 ns	1,327.09 ns	74.983 ns	1.06	0.05	-	0 B

BenchmarkDotNet=v0.10.13, OS=Windows 10 Redstone 3 [1709, Fall Creators Update] (10.0.16299.309)
Intel Core i7-8550U CPU 1.80GHz (Kaby Lake R), 1 CPU, 8 logical cores and 4 physical cores
Frequency=1945315 Hz, Resolution=514.0556 ns, Timer=TSC
.NET Core SDK=2.1.300-preview3-008414
  [Host]   : .NET Core 2.1.0-preview3-26327-02 (CoreCLR 4.6.26327.05, CoreFX 4.6.26327.03), 64bit RyuJIT
  ShortRun : .NET Core 2.1.0-preview3-26327-02 (CoreCLR 4.6.26327.05, CoreFX 4.6.26327.03), 64bit RyuJIT

Job=ShortRun  LaunchCount=1  TargetCount=3
WarmupCount=3

Method	Repeats	Mean	Error	StdDev	Scaled	ScaledSD	Gen 0	Allocated
ConsumeTask	100	748.2 ns	352.92 ns	19.941 ns	1.91	0.05	1.7328	7272 B
ConsumeValueTaskWrong	100	1,186.9 ns	55.53 ns	3.138 ns	3.03	0.04	-	0 B
ConsumeValueTaskProperly	100	391.2 ns	120.52 ns	6.810 ns	1.00	0.00	-	0 B
ConsumeValueTaskCrazy	100	276.1 ns	64.72 ns	3.657 ns	0.71	0.01	-	0 B
ConsumeTask	1000	7,340.3 ns	3,718.01 ns	210.074 ns	1.96	0.05	17.1814	72072 B
ConsumeValueTaskWrong	1000	18,480.7 ns	69,049.35 ns	3,901.416 ns	4.93	0.85	-	0 B
ConsumeValueTaskProperly	1000	3,747.5 ns	1,227.71 ns	69.368 ns	1.00	0.00	-	0 B
ConsumeValueTaskCrazy	1000	2,576.6 ns	345.06 ns	19.496 ns	0.69	0.01	-	0 B

Task Improvements

Before

BenchmarkDotNet=v0.10.13, OS=Windows 10 Redstone 3 [1709, Fall Creators Update] (10.0.16299.309)
Intel Core i7-8550U CPU 1.80GHz (Kaby Lake R), 1 CPU, 8 logical cores and 4 physical cores
Frequency=1945315 Hz, Resolution=514.0556 ns, Timer=TSC
.NET Core SDK=2.1.300-preview3-008414
  [Host]     : .NET Core 2.0.6 (CoreCLR 4.6.26212.01, CoreFX 4.6.26212.01), 64bit RyuJIT
  Job-HZSBKB : .NET Core 2.0.6 (CoreCLR 4.6.26212.01, CoreFX 4.6.26212.01), 64bit RyuJIT

Toolchain=.NET Core 2.0  LaunchCount=1  TargetCount=3  
WarmupCount=3  

Method	Mean	Error	StdDev	Scaled	Allocated
Return	15.576 ms	0.4185 ms	0.0236 ms	1.00	528 B
Simple	15.568 ms	0.8275 ms	0.0468 ms	1.00	744 B
Actions	2.008 ms	0.0756 ms	0.0043 ms	0.13	560 B

After

BenchmarkDotNet=v0.10.13, OS=Windows 10 Redstone 3 [1709, Fall Creators Update] (10.0.16299.309)
Intel Core i7-8550U CPU 1.80GHz (Kaby Lake R), 1 CPU, 8 logical cores and 4 physical cores
Frequency=1945315 Hz, Resolution=514.0556 ns, Timer=TSC
.NET Core SDK=2.1.300-preview3-008414
  [Host]     : .NET Core 2.1.0-preview3-26327-02 (CoreCLR 4.6.26327.05, CoreFX 4.6.26327.03), 64bit RyuJIT
  Job-SLQOHY : .NET Core 2.1.0-preview3-26327-02 (CoreCLR 4.6.26327.05, CoreFX 4.6.26327.03), 64bit RyuJIT

Toolchain=2.1-preview3  LaunchCount=1  TargetCount=3  
WarmupCount=3  

Method	Mean	Error	StdDev	Scaled	Allocated
Return	15.542 ms	1.3313 ms	0.0752 ms	1.00	376 B
Simple	15.538 ms	1.4433 ms	0.0815 ms	1.00	488 B
Actions	1.939 ms	0.4590 ms	0.0259 ms	0.12	350 B

Links

• Avoid async delegate allocation
• Reduce allocations when async methods yield
• State of the .NET Performance - Adam Sitnik