Improving sdk install performance

[sebastienros]

I noticed that every time I would run build.cmd it is taking an unreasonable amount of time to detect that I already have the required runtimes locally in .\.dotnet. I managed to improve this time by using this check in tools.ps1:

function InstallDotNet([string] $dotnetRoot,
  [string] $version,
  [string] $architecture = '',
  [string] $runtime = '',
  [bool] $skipNonVersionedFiles = $false,
  [string] $runtimeSourceFeed = '',
  [string] $runtimeSourceFeedKey = '',
  [switch] $noPath) {

  # BEGIN
  $runtimePath = $dotnetRoot

  $runtimePath = $runtimePath + "\shared"
  if ($runtime -eq "dotnet") { $runtimePath = $runtimePath + "\Microsoft.NETCore.App" }
  if ($runtime -eq "aspnetcore") { $runtimePath = $runtimePath + "\Microsoft.AspNetCore.App" }
  $runtimePath = $runtimePath + "\" + $version

  if (Test-Path $runtimePath) {
    $installSuccess = $true
    Exit
  }
  # END

  $installScript = GetDotNetInstallScript $dotnetRoot
  $installParameters = @{
    Version = $version

I believe that just loading dotnet-install.ps1 is already costly, and on repositories that target multiple runtimes it is accumulating quickly. On my previous machine with aspnetcore it would spend 10s for nothing on each build.

But I think this could be improved even more if the calls to dotnet-install.cmd were skipped altogether and that would performance even better since it would prevent from starting a cmd which itself calls powershell then loads the scripts, for each runtime in global.json. My solution is barely skipping the dotnet-install.ps1 invocation.

[markwilkie]

I'd be open to a PR on this @sebastienros.

[sebastienros]

I am glad you are suggesting it as I didn't want to start anything if you had reasons not do accept changes around that. Thanks

[RussKie]

This has been bothering me too. It's both too time consuming and too noisy. I have already made changes to dotnet-install scripts to reduce the chattiness.

I see there are possibly few ways of achieving the improvement. Probably the easiest option is to add a new switch - e.g., --skip-restore-toolset | -srt - that would bypass this command:

arcade/eng/common/dotnet-install.ps1

Line 20 in fb14cae

InstallDotNet $installdir $version $architecture $runtime $true -RuntimeSourceFeed $RuntimeSourceFeed -RuntimeSourceFeedKey $RuntimeSourceFeedKey

This way for the first time a dev will need to run .\restore.cmd to install the required toolsets, and then run .\restore.cmd -srt to only install the SDK, if required.

A more hands-off kind of solution could be building the runtime-pack paths and then conditionally run the above command.