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Merged
ToddGrun merged 2 commits into from
Apr 29, 2025
Merged

Optimize work done in ProjectCodeModelFactory #78369

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Optimize work done in ProjectCodeModelFactory
ToddGrun Apr 29, 2025
2767cec
use passed in CT
ToddGrun Apr 29, 2025
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181 changes: 112 additions & 69 deletions src/VisualStudio/Core/Impl/CodeModel/ProjectCodeModelFactory.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
Expand All @@ -15,6 +16,7 @@
using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.TestHooks;
using Microsoft.CodeAnalysis.Threading;
using Microsoft.VisualStudio.Shell;
Expand All @@ -33,7 +35,7 @@ internal sealed class ProjectCodeModelFactory : IProjectCodeModelFactory
private readonly IServiceProvider _serviceProvider;
private readonly IThreadingContext _threadingContext;

private readonly AsyncBatchingWorkQueue<DocumentId> _documentsToFireEventsFor;
private readonly AsyncBatchingWorkQueue<WorkspaceChangeEventArgs> _workspaceChangeEventsToFireEventsFor;

[ImportingConstructor]
[Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
Expand All @@ -52,12 +54,9 @@ public ProjectCodeModelFactory(
// Queue up notifications we hear about docs changing. that way we don't have to fire events multiple times
// for the same documents. Once enough time has passed, take the documents that were changed and run
// through them, firing their latest events.
_documentsToFireEventsFor = new AsyncBatchingWorkQueue<DocumentId>(
_workspaceChangeEventsToFireEventsFor = new AsyncBatchingWorkQueue<WorkspaceChangeEventArgs>(
DelayTimeSpan.Idle,
ProcessNextDocumentBatchAsync,
// We only care about unique doc-ids, so pass in this comparer to collapse streams of changes for a
// single document down to one notification.
EqualityComparer<DocumentId>.Default,
ProcessNextWorkspaceChangeEventBatchAsync,
Listener,
threadingContext.DisposalToken);

Expand All @@ -66,61 +65,65 @@ public ProjectCodeModelFactory(

internal IAsynchronousOperationListener Listener { get; }

private async ValueTask ProcessNextDocumentBatchAsync(
ImmutableSegmentedList<DocumentId> documentIds, CancellationToken cancellationToken)
private async ValueTask ProcessNextWorkspaceChangeEventBatchAsync(
ImmutableSegmentedList<WorkspaceChangeEventArgs> workspaceChangeEvents, CancellationToken cancellationToken)
{
// This logic preserves the previous behavior we had with IForegroundNotificationService.
// Specifically, we don't run on the UI thread for more than 15ms at a time. And once we
// have, we wait 50ms before continuing. These constants are just what we defined from
// legacy, and otherwise have no special meaning.
const int MaxTimeSlice = 15;
var delayBetweenProcessing = DelayTimeSpan.NearImmediate;

Debug.Assert(!_threadingContext.JoinableTaskContext.IsOnMainThread, "The following context switch is not expected to cause runtime overhead.");
await TaskScheduler.Default;

// Ensure MEF services used by the code model are initially obtained on a background thread.
// This code avoids allocations where possible.
// https://github.com/dotnet/roslyn/issues/54159
string? previousLanguage = null;
foreach (var projectState in _visualStudioWorkspace.CurrentSolution.SolutionState.SortedProjectStates)
{
if (projectState.Language == previousLanguage)
{
// Avoid duplicate calls if the language did not change
continue;
}
// Calculate the full set of changes over this set of events while on a background thread.
using var _1 = PooledHashSet<DocumentId>.GetInstance(out var documentIds);
AddChangedDocuments(workspaceChangeEvents, documentIds);

previousLanguage = projectState.Language;
projectState.LanguageServices.GetService<ICodeModelService>();
projectState.LanguageServices.GetService<ISyntaxFactsService>();
projectState.LanguageServices.GetService<ICodeGenerationService>();
}
if (documentIds.Count == 0)
return;

// get the file path information while on a background thread
using var _2 = ArrayBuilder<(ProjectCodeModel projectCodeModel, string filename)>.GetInstance(out var projectCodeModelAndFileNames);
AddProjectCodeModelAndFileNames(documentIds, projectCodeModelAndFileNames);

// Ensure MEF services used by the code model are initially obtained on a background thread.
EnsureServicesCreated();

await _threadingContext.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);

var stopwatch = SharedStopwatch.StartNew();
foreach (var documentId in documentIds)
// Fire off the code model events while on the main thread
await FireEventsForChangedDocumentsAsync(projectCodeModelAndFileNames, cancellationToken).ConfigureAwait(false);
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@CyrusNajmabadi CyrusNajmabadi Apr 29, 2025

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nit: since this method is async, you can move the STMTA into it.

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@ToddGrun ToddGrun Apr 29, 2025

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I actually kind of preferred it in the outer method, as that's what's done for the background thread assurance. This way, if more work needs to be done on the main thread, it can just be called from the same section in ProcessNextWorkspaceChangeEventBatchAsync.

}

private static void AddChangedDocuments(ImmutableSegmentedList<WorkspaceChangeEventArgs> workspaceChangeEvents, PooledHashSet<DocumentId> documentIds)
{
if (workspaceChangeEvents.All(static e => e.Kind is WorkspaceChangeKind.DocumentRemoved or WorkspaceChangeKind.DocumentChanged))
{
FireEventsForDocument(documentId);
// Fast path when we know we affected a document that could have had code model elements in it. No
// need to do a solution diff in this case.
foreach (var e in workspaceChangeEvents)
documentIds.Add(e.DocumentId!);

// Keep firing events for this doc, as long as we haven't exceeded the max amount
// of waiting time, and there's no user input that should take precedence.
if (stopwatch.Elapsed.TotalMilliseconds > MaxTimeSlice || IsInputPending())
{
await this.Listener.Delay(delayBetweenProcessing, cancellationToken).ConfigureAwait(true);
stopwatch = SharedStopwatch.StartNew();
}
return;
}

return;
// Contains an event that could indicate a doc change/removal. Have to actually analyze the change to
// determine what we should do here.
var oldSolution = workspaceChangeEvents[0].OldSolution;
var newSolution = workspaceChangeEvents[^1].NewSolution;

var changes = oldSolution.GetChanges(newSolution);

void FireEventsForDocument(DocumentId documentId)
foreach (var project in changes.GetRemovedProjects())
documentIds.AddRange(project.DocumentIds);

foreach (var projectChange in changes.GetProjectChanges())
{
// If we've been asked to shutdown, don't bother reporting any more events.
if (_threadingContext.DisposalToken.IsCancellationRequested)
return;
documentIds.AddRange(projectChange.GetRemovedDocuments());
documentIds.AddRange(projectChange.GetChangedDocuments());
}
}

private void AddProjectCodeModelAndFileNames(HashSet<DocumentId> documentIds, ArrayBuilder<(ProjectCodeModel, string)> projectCodeModelAndFileNames)
{
foreach (var documentId in documentIds)
{
var projectCodeModel = this.TryGetProjectCodeModel(documentId.ProjectId);
if (projectCodeModel == null)
return;
Expand All @@ -129,12 +132,52 @@ void FireEventsForDocument(DocumentId documentId)
if (filename == null)
return;

if (!projectCodeModel.TryGetCachedFileCodeModel(filename, out var fileCodeModelHandle))
projectCodeModelAndFileNames.Add((projectCodeModel, filename));
}
}

private async Task FireEventsForChangedDocumentsAsync(
ArrayBuilder<(ProjectCodeModel projectCodeModel, string filename)> projectCodeModelAndFileNames,
CancellationToken cancellationToken)
{
// This logic preserves the previous behavior we had with IForegroundNotificationService.
// Specifically, we don't run on the UI thread for more than 15ms at a time. And we don't
// check the input queue more than once per ms. Once we have run for more than 15 ms,
// we wait 50ms before continuing. These constants are just what we defined from
// legacy, and otherwise have no special meaning.
const int MaxTimeSlice = 15;
double nextInputCheckElapsedMs = 1;

var stopwatch = SharedStopwatch.StartNew();
foreach (var (projectCodeModel, filename) in projectCodeModelAndFileNames)
{
// If we've been asked to shutdown, don't bother reporting any more events.
if (_threadingContext.DisposalToken.IsCancellationRequested)
return;

var codeModel = fileCodeModelHandle.Object;
codeModel.FireEvents();
return;
FireEventsForDocument(projectCodeModel, filename);

// Keep firing events for this doc, as long as we haven't exceeded MaxTimeSlice ms or input isn't pending.
// We'll validate against those constraints at most once every 1 ms, to avoid spam checking the
// input queue, as this has shown up in performance profiles.
var elapsedMs = stopwatch.Elapsed.TotalMilliseconds;
if (elapsedMs > nextInputCheckElapsedMs)
{
if (elapsedMs > MaxTimeSlice || IsInputPending())
{
await this.Listener.Delay(DelayTimeSpan.NearImmediate, cancellationToken).ConfigureAwait(true);
stopwatch = SharedStopwatch.StartNew();
elapsedMs = 0;
}

nextInputCheckElapsedMs = elapsedMs + 1;
}
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@CyrusNajmabadi CyrusNajmabadi Apr 29, 2025

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i assume this logic was the same as before.

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@ToddGrun ToddGrun Apr 29, 2025

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This logic changed, as IsInputPending showed up in the profiles

}

static void FireEventsForDocument(ProjectCodeModel projectCodeModel, string filename)
{
if (projectCodeModel.TryGetCachedFileCodeModel(filename, out var fileCodeModelHandle))
fileCodeModelHandle.Object.FireEvents();
}

// Returns true if any keyboard or mouse button input is pending on the message queue.
Expand All @@ -153,6 +196,24 @@ static bool IsInputPending()
}
}

private void EnsureServicesCreated()
{
// Ensure MEF services used by the code model are initially obtained on a background thread.
// This code avoids allocations where possible.
// https://github.com/dotnet/roslyn/issues/54159
using var _ = PooledHashSet<string>.GetInstance(out var previousLanguages);
foreach (var projectState in _visualStudioWorkspace.CurrentSolution.SolutionState.SortedProjectStates)
{
// Avoid duplicate calls if the language has been seen
if (previousLanguages.Add(projectState.Language))
{
projectState.LanguageServices.GetService<ICodeModelService>();
projectState.LanguageServices.GetService<ISyntaxFactsService>();
projectState.LanguageServices.GetService<ICodeGenerationService>();
}
}
}

private void OnWorkspaceChanged(WorkspaceChangeEventArgs e)
{
// Events that can't change existing code model items. Can just ignore them.
Expand All @@ -170,27 +231,9 @@ private void OnWorkspaceChanged(WorkspaceChangeEventArgs e)
case WorkspaceChangeKind.AnalyzerConfigDocumentReloaded:
case WorkspaceChangeKind.AnalyzerConfigDocumentChanged:
return;
case WorkspaceChangeKind.DocumentRemoved:
case WorkspaceChangeKind.DocumentChanged:
// Fast path when we know we affected a document that could have had code model elements in it. No
// need to do a solution diff in this case.
_documentsToFireEventsFor.AddWork(e.DocumentId!);
return;
}

// Other type of event that could indicate a doc change/removal. Have to actually analyze the change to
// determine what we should do here.

var changes = e.OldSolution.GetChanges(e.NewSolution);

foreach (var project in changes.GetRemovedProjects())
_documentsToFireEventsFor.AddWork(project.DocumentIds);

foreach (var projectChange in changes.GetProjectChanges())
{
_documentsToFireEventsFor.AddWork(projectChange.GetRemovedDocuments());
_documentsToFireEventsFor.AddWork(projectChange.GetChangedDocuments());
}
_workspaceChangeEventsToFireEventsFor.AddWork(e);
}

public IProjectCodeModel CreateProjectCodeModel(ProjectId id, ICodeModelInstanceFactory codeModelInstanceFactory)
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