Reduce blocking time in UpdateSolution_QueryDelayBuildAction

[Erarndt]

Bug

Fixes:

Description

Users are reporting that there is an occasional lengthy delay before build starts. Some early telemetry shows that it can take over 10s just to construct the IVsTask that gets returned. This isn't the time to finish the restore that the task initiates.

The code now unconditionally yields as a first step to return to the caller immediately. Additionally, switching to explicit GetExport() calls avoid some of the cost associated with SatisfyImportsOnce(). There might be a few innacuracies here, but it looks like there were some recent exports/services that were added that could explain why the MEF construction is showing up now:

• CopilotToolInvocationService.cs
• FixVulnerablitiesService.cs
• VulnerablePackagesInfoBar.cs (IVulnerabilitiesNotificationService)
• AuditCheckResultCachingService.cs
• InfiniteScrollListViewModel
• LegacyProjectAdapter
• several PackageSourceMapping options pages

PR Checklist

• Meaningful title, helpful description and a linked NuGet/Home issue
• Added tests
• Link to an issue or pull request to update docs if this PR changes settings, environment variables, new feature, etc.

[Nigusu-Allehu]

Let's update the PR title

[Erarndt]

Let's update the PR title

Updated :)

[donnie-msft]

Is there evidence that this is resolving the issue you described, or is it just something to try and observe its impact?

Had a few questions inline...

[donnie-msft]

it looks like there were some recent exports/services that were added that could explain why the MEF construction is showing up now:

I'm not understanding some of the listed items. Such as:

several PackageSourceMapping options pages

I assume this means VS Options pages, such as PackageSourceMapping. There are no MEF imports in this page, but it does rely on VSSettings which comes from a MEF import in NuGet's AsyncPackage in one initial place - NuGetPackage.cs, and it is shared among those settings pages.

[Nigusu-Allehu]

LGTM

[Erarndt]

Is there evidence that this is resolving the issue you described, or is it just something to try and observe its impact?

Had a few questions inline...

I do not have a way to reproduce the issue locally, so I can't directly validate the fix. I had to use telemetry to diagnose the issue in the wild.

There are multiple instrumentation points, and the issue I'm attempting to address in this PR is the synchronous blocking in UpdateSolution_QueryDelayBuildAction() before the IVsTask is returned. The duration of the IVsTask completion is captured in a separate telemetry event. The call to RestoreAsync() immediately yields, so it can't be the culprit. There's not much other code here, and the most likely issue is the code in the JTF.Run(). Moving the blocking code into the task is sufficient to avoid the synchronous block.

The change to the import flow isn't required to stop the synchronous blocking, but telemetry indicates that this code is rather slow (taking over 17s in a few instances). This was my attempt at speeding things up.

[Erarndt]

it looks like there were some recent exports/services that were added that could explain why the MEF construction is showing up now:

I'm not understanding some of the listed items. Such as:

several PackageSourceMapping options pages

I assume this means VS Options pages, such as PackageSourceMapping. There are no MEF imports in this page, but it does rely on VSSettings which comes from a MEF import in NuGet's AsyncPackage in one initial place - NuGetPackage.cs, and it is shared among those settings pages.

It's entirely possible that list is inaccurate. That was a quick attempt to see what might have changed to make this path slower recently. This seems like a relatively new issue, so I took a quick look. I can't reproduce this locally, so I can't profile.

[nkolev92]

This needs a rebase on top of latest dev @Erarndt

[Erarndt]

This needs a rebase on top of latest dev @Erarndt

Rebased. Looks like the last NuGet.Clinet-VS run had some failures, but the tests history either looks flaky or has been failing consistently across runs. Do you see anything that I introduced?