briantist

Question

我编写了一个PowerShell脚本，需要在函数之间传递大字节数组。该脚本缓慢运行极。下面的示例代码重现了该问题。它只是将一个10 MiB数组传递给一个什么都不做的函数（除了记录消息），并测量调用所需的时间。

function do-nothing
{
    param($foo)
    Write-Verbose -Verbose "in the function"
}

$tenMiB = 10 * 1024 * 1024
$myFoo = New-Object byte[] $tenMiB

Write-Verbose -Verbose "about to do call a function that does nothing..."
$elapsed = Measure-Command -Expression { do-nothing -foo $myFoo }
Write-Verbose -Verbose "doing nothing took $($elapsed.TotalMilliseconds) milliseconds"

我希望这需要几毫秒。在我的家用电脑上，它需要将近3000毫秒，并以100％的速度运行CPU核心。我使用PowerShell 4和PowerShell 5（预生产版本）获得了相同的结果。我的工作PC和服务器也发生了同样的事情。但是，一位同事获得了预期的结果 - 执行几毫秒，CPU使用率最低。

执行时间大致与数组的大小成正比，这对我来说毫无意义。数组的大小无关紧要。

我想知道数组是否以某种方式被复制。我不认为是这种情况，因为在数组上调用GetHashCode()会在函数内部和外部返回相同的值。

如果数组包装在PSCustomObject中，并且包装器被传递给函数，则代码将按预期执行。作为一种解决方法，这有点难看，我宁愿在诉诸之前了解正在发生的事情。

有人能解释一下看似奇怪的行为吗？

Answer 1

我将此作为社区维基发布，旨在成为我们可以发布个人环境和测试结果的地方，因为再现似乎有些麻烦。也许我们可以找出造成这种情况的条件，并从那里确定为什么它在实例中的速度很慢。欢迎格式化建议/更改。

briantist

工作站

HW（i7）

Windows 8.1

PowerShell 4.0

ISE和控制台

已加入域名

byte[]结果：~3,500ms

object[]结果：~6,500ms

服务器VM

VM（VMware ESXi）

Windows 2012 R2

PowerShell 5.0.10514.6（生产预览）

ISE

已加入域名

byte[]结果：＆gt; 7,000ms

object[]结果：~100ms

家庭工作站



HW（i5）

Windows 10 build 1511

PowerShell 5

ISE和控制台

工作组（无AD）

结果：首次运行4-6ms，＆lt; 2ms后续运行


emanresu



PowerShell 4

结果：1.8 - 2.4ms


Bacon Bits

工作站



Windows 7 x64 SP1

已加入域名

PowerShell 4

结果：100次执行，平均1.16ms，最小0.67ms，最大13.88ms，1.39ms stddev


VM（ESXi）



Windows Server 2012 R2

已加入域名

PowerShell 4

结果：10次执行，平均4221ms，最小4173ms，最大4302ms，38.54ms stddev


Ansgar Wiechers

VM（VirtualBox）



Windows 2012 R2（vanilla安装）

PowerShell 4
  CLRVersion：4.0.30319.34014
  BuildVersion：6.3.9600.16394

结果：~7.5ms



Windows 2012 R2（相同的VM，已完全修补）

PowerShell 4
  CLRVersion：4.0.30319.34209
  BuildVersion：6.3.9600.17400

结果：~4000ms




进一步调查显示该问题是由2014年11月更新汇总（MSKB 3000850）引入的。但不确定哪些收集的修补程序是真正的罪魁祸首。

beatcracker

桌面



HW：Q6600@3.1 GHz / 8GB RAM

Windows Server 2012

工作组（无AD）

PowerShell 5（5.0.10018.0）

ISE和控制台

结果：~5000ms


笔记本



HW：i3@2.5 GHz / 4GB RAM

Windows 8.1

加入域名的PC

PowerShell 4

ISE和控制台

结果：~6000ms


David Brabant



PowerShell 5

Windows 10

结果：＆lt; 7毫秒


sodawillow



HW（i5）

Windows 8.1

工作组（无AD）

PowerShell 5.0.10514.6

ISE

结果：＆gt; 3500毫秒


Mathias R. Jessen

家用笔记本电脑



HW（i7-2620M）

Windows 10（版本10240）

PowerShell 5.0

ISE和控制台

byte[]结果：~5,350ms

object[]结果：~8,500ms

int[]结果：~9,700ms

Answer 2

感谢@Ansgar Wiechers发布的stack traces，我能够在我的PC上重现这种行为（Windows 10 build 1511，PowerShell 5.0.10586.0），代码如下：

$Module = New-Module {
    function do-nothing
    {
        param($foo)
        Write-Verbose -Verbose "in the function"
    }
}
$Module.LogPipelineExecutionDetails = $true

$myFoo = New-Object byte[] 10mb

Write-Verbose -Verbose "about to do call a function that does nothing..."
$elapsed = Measure-Command -Expression { do-nothing -foo $myFoo }
Write-Verbose -Verbose "doing nothing took $($elapsed.TotalMilliseconds) milliseconds"

启用LogPipelineExecutionDetails会导致函数执行速度大幅下降。从我对ILSpy的挖掘来看，只有当函数属于模块并且模块启用此选项时，才应启用管道执行细节的记录。也许这是kb3000850改变的确切行为。

如果do-nothing属于模块，但LogPipelineExecutionDetails明确设置为$false，则会重现问题会很有趣。

Answer 3

补充信息，作为额外的社区维基回答发布，以避免每个答案的字符限制。

根据@PetSerAl的要求，我在安装kb3000850之前和之后运行了以下代码：

Add-Type -TypeDefinition @'
public static class C{
  public static System.Collections.IEnumerable M(){
    System.Console.WriteLine(new System.Diagnostics.StackTrace());
    yield break;
  }
}
'@

function do-nothing {
  param($foo)
  Write-Verbose -Verbose "in the function"
}

$myFoo = [C]::M()

Write-Verbose -Verbose "about to do call a function that does nothing..."
$elapsed = Measure-Command -Expression { do-nothing -foo $myFoo }
Write-Verbose -Verbose "doing nothing took $($elapsed.TotalMilliseconds) milliseconds"

更新前的Stacktrace：

at C.<M>d__0.MoveNext()
at System.Management.Automation.PSObject.ToStringEnumerable(ExecutionContext context, IEnumerable enumerable, String separator, String format, IFormatProvider formatProvider)
at System.Management.Automation.PSObject.ToString(ExecutionContext context, Object obj, String separator, String format, IFormatProvider formatProvider, Boolean recurse, Boolean unravelEnumeratorOnRecurse)
at System.Management.Automation.PSObject.ToStringParser(ExecutionContext context, Object obj)
at System.Management.Automation.LanguagePrimitives.ConvertNonNumericToString(Object valueToConvert, Type resultType, Boolean recursion, PSObject originalValueToConvert, IFormatProvider formatProvider, TypeTable backupTable)
at System.Management.Automation.LanguagePrimitives.ConversionData`1.Invoke(Object valueToConvert, Type resultType, Boolean recurse, PSObject originalValueToConvert, IFormatProvider formatProvider, TypeTable backupTable)
at System.Management.Automation.LanguagePrimitives.ConvertTo(Object valueToConvert, Type resultType, Boolean recursion, IFormatProvider formatProvider, TypeTable backupTypeTable)
at System.Management.Automation.ParameterBinderBase.CoerceTypeAsNeeded(CommandParameterInternal argument, String parameterName, Type toType, ParameterCollectionTypeInformation collectionTypeInfo, Object currentValue)
at System.Management.Automation.ParameterBinderBase.BindParameter(CommandParameterInternal parameter, CompiledCommandParameter parameterMetadata, ParameterBindingFlags flags)
at System.Management.Automation.CmdletParameterBinderController.BindParameter(CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
at System.Management.Automation.CmdletParameterBinderController.BindParameter(UInt32 parameterSets, CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
at System.Management.Automation.ParameterBinderController.BindPositionalParametersInSet(UInt32 validParameterSets, Dictionary`2 nextPositionalParameters, CommandParameterInternal argument, ParameterBindingFlags flags, ParameterBindingException& bindingException)
at System.Management.Automation.ParameterBinderController.BindPositionalParameters(Collection`1 unboundArguments, UInt32 validParameterSets, UInt32 defaultParameterSet, ParameterBindingException& outgoingBindingException)
at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParametersNoValidation(Collection`1 arguments)
at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParameters(Collection`1 arguments)
at System.Management.Automation.CommandProcessor.BindCommandLineParameters()
at System.Management.Automation.CommandProcessorBase.DoPrepare(IDictionary psDefaultParameterValues)
at System.Management.Automation.Internal.PipelineProcessor.Start(Boolean incomingStream)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.ScriptBlock.InvokeWithPipeImpl(ScriptBlockClauseToInvoke clauseToInvoke, Boolean createLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at System.Management.Automation.ScriptBlock.<>c__DisplayClassa.<InvokeWithPipe>b__8()
at System.Management.Automation.Runspaces.RunspaceBase.RunActionIfNoRunningPipelinesWithThreadCheck(Action action)
at System.Management.Automation.ScriptBlock.InvokeWithPipe(Boolean useLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at Microsoft.PowerShell.Commands.MeasureCommandCommand.ProcessRecord()
at System.Management.Automation.CommandProcessor.ProcessRecord()
at System.Management.Automation.CommandProcessorBase.DoExecute()
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.Runspaces.LocalPipeline.InvokeHelper()
at System.Management.Automation.Runspaces.LocalPipeline.InvokeThreadProc()
at System.Management.Automation.Runspaces.PipelineThread.WorkerProc()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

更新后的堆栈跟踪（突出显示差异）：

at C.<M>d__0.MoveNext()
at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
at System.Management.Automation.ParameterBinderBase.BindParameter(CommandParameterInternal parameter, CompiledCommandParameter parameterMetadata, ParameterBindingFlags flags)
at System.Management.Automation.ParameterBinderController.BindParameter(UInt32 parameterSets, CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
at System.Management.Automation.ScriptParameterBinderController.BindParameters(Collection`1 arguments)
at System.Management.Automation.ScriptParameterBinderController.BindCommandLineParameters(Collection`1 arguments)
at System.Management.Automation.DlrScriptCommandProcessor.EnterScope()
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.ScriptBlock.InvokeWithPipeImpl(ScriptBlockClauseToInvoke clauseToInvoke, Boolean createLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at System.Management.Automation.ScriptBlock.<>c__DisplayClassa.<InvokeWithPipe>b__8()
at System.Management.Automation.Runspaces.RunspaceBase.RunActionIfNoRunningPipelinesWithThreadCheck(Action action)
at System.Management.Automation.ScriptBlock.InvokeWithPipe(Boolean useLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at Microsoft.PowerShell.Commands.MeasureCommandCommand.ProcessRecord()
at System.Management.Automation.CommandProcessor.ProcessRecord()
at System.Management.Automation.CommandProcessorBase.DoExecute()
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.Runspaces.LocalPipeline.InvokeHelper()
at System.Management.Automation.Runspaces.LocalPipeline.InvokeThreadProc()
at System.Management.Automation.Runspaces.PipelineThread.WorkerProc()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

at C.<M>d__0.MoveNext()
at System.Management.Automation.PSObject.ToStringEnumerable(ExecutionContext context, IEnumerable enumerable, String separator, String format, IFormatProvider formatProvider)
at System.Management.Automation.PSObject.ToString(ExecutionContext context, Object obj, String separator, String format, IFormatProvider formatProvider, Boolean recurse, Boolean unravelEnumeratorOnRecurse)
at System.Management.Automation.PSObject.ToStringParser(ExecutionContext context, Object obj)
at System.Management.Automation.LanguagePrimitives.ConvertNonNumericToString(Object valueToConvert, Type resultType, Boolean recursion, PSObject originalValueToConvert, IFormatProvider formatProvider, TypeTable backupTable)
at System.Management.Automation.LanguagePrimitives.ConversionData`1.Invoke(Object valueToConvert, Type resultType, Boolean recurse, PSObject originalValueToConvert, IFormatProvider formatProvider, TypeTable backupTable)
at System.Management.Automation.LanguagePrimitives.ConvertTo(Object valueToConvert, Type resultType, Boolean recursion, IFormatProvider formatProvider, TypeTable backupTypeTable)
at System.Management.Automation.LanguagePrimitives.ConvertTo(Object valueToConvert, Type resultType, IFormatProvider formatProvider)
at System.Management.Automation.ParameterBinderBase.CoerceTypeAsNeeded(CommandParameterInternal argument, String parameterName, Type toType, ParameterCollectionTypeInformation collectionTypeInfo, Object currentValue)
at System.Management.Automation.ParameterBinderBase.BindParameter(CommandParameterInternal parameter, CompiledCommandParameter parameterMetadata, ParameterBindingFlags flags)
at System.Management.Automation.CmdletParameterBinderController.BindParameter(CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
at System.Management.Automation.CmdletParameterBinderController.BindParameter(UInt32 parameterSets, CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
at System.Management.Automation.ParameterBinderController.BindPositionalParametersInSet(UInt32 validParameterSets, Dictionary`2 nextPositionalParameters, CommandParameterInternal argument, ParameterBindingFlags flags, ParameterBindingException& bindingException)
at System.Management.Automation.ParameterBinderController.BindPositionalParameters(Collection`1 unboundArguments, UInt32 validParameterSets, UInt32 defaultParameterSet, ParameterBindingException& outgoingBindingException)
at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParametersNoValidation(Collection`1 arguments)
at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParameters(Collection`1 arguments)
at System.Management.Automation.CommandProcessor.BindCommandLineParameters()
at System.Management.Automation.CommandProcessorBase.DoPrepare(IDictionary psDefaultParameterValues)
at System.Management.Automation.Internal.PipelineProcessor.Start(Boolean incomingStream)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.ScriptBlock.InvokeWithPipeImpl(ScriptBlockClauseToInvoke clauseToInvoke, Boolean createLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at System.Management.Automation.ScriptBlock.<>c__DisplayClassa.<InvokeWithPipe>b__8()
at System.Management.Automation.Runspaces.RunspaceBase.RunActionIfNoRunningPipelinesWithThreadCheck(Action action)
at System.Management.Automation.ScriptBlock.InvokeWithPipe(Boolean useLocalScope, Dictionary`2 functionsToDefine, List`1 variablesToDefine, ErrorHandlingBehavior errorHandlingBehavior, Object dollarUnder, Object input, Object scriptThis, Pipe outputPipe, InvocationInfo invocationInfo, Object[] args)
at Microsoft.PowerShell.Commands.MeasureCommandCommand.ProcessRecord()
at System.Management.Automation.CommandProcessor.ProcessRecord()
at System.Management.Automation.CommandProcessorBase.DoExecute()
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.Interpreter.Run(InterpretedFrame frame)
at System.Management.Automation.Interpreter.LightLambda.RunVoid1[T0](T0 arg0)
at System.Management.Automation.DlrScriptCommandProcessor.RunClause(Action`1 clause, Object dollarUnderbar, Object inputToProcess)
at System.Management.Automation.DlrScriptCommandProcessor.Complete()
at System.Management.Automation.CommandProcessorBase.DoComplete()
at System.Management.Automation.Internal.PipelineProcessor.DoCompleteCore(CommandProcessorBase commandRequestingUpstreamCommandsToStop)
at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
at System.Management.Automation.Runspaces.LocalPipeline.InvokeHelper()
at System.Management.Automation.Runspaces.LocalPipeline.InvokeThreadProc()
at System.Management.Automation.Runspaces.PipelineThread.WorkerProc()
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Answer 4

VERBOSE: about to do call a function that does nothing...
VERBOSE: in the function
VERBOSE: doing nothing took 9345.0445 milliseconds

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_ref?view=powershell-7.1#writing-functions-to-accept-reference-parameters

function do-nothing
{
    param([ref]$foo)
    # When using references, you must use the Value property of
    # the System.Management.Automation.PSReference type to access your data.
    $foo.Value 
    Write-Verbose -Verbose "in the function"
}

$tenMiB = 10 * 1024 * 1024
$myFoo = New-Object byte[] $tenMiB

Write-Verbose -Verbose "about to do call a function that does nothing..."
$elapsed = Measure-Command -Expression { do-nothing -foo ([ref]$myFoo) }
Write-Verbose -Verbose "doing nothing took $($elapsed.TotalMilliseconds) milliseconds"

_

VERBOSE: about to do call a function that does nothing...
VERBOSE: in the function
VERBOSE: doing nothing took 1303.8049 milliseconds

将数组传递给函数的速度非常慢

4 个答案:

briantist

工作站

服务器VM

家庭工作站

emanresu

Bacon Bits

工作站

VM（ESXi）

Ansgar Wiechers

VM（VirtualBox）

beatcracker

桌面

笔记本

David Brabant

sodawillow

Mathias R. Jessen

家用笔记本电脑