.Ipynb in VS Code has long delay after printing

[jhoneill]

Describe the bug

It takes >6 seconds to return after printing <200 characters.

Please complete the following:

.NET Interactive
© 2020 Microsoft Corporation
Version: 1.0.260601+9d1ecd3c06ba93e59bfef3842d2660c08d9e2ce5
Build date: 2021-12-18T10:36:48.0565225Z

• OS
  • Windows 11
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• Browser
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• Frontend
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Screenshots

Here is a trivial bit of powerShell

#!time 
$sw = [System.Diagnostics.Stopwatch]::new()
$sw.Start()
1..90
"Elapsed ms:$($sw.ElapsedMilliseconds)"
$sw.stop()

It prints numbers 1 to 90 and gives the elapsed time by two methods the screen shot shows it took 6.4 seconds to return

The messages above are printed after a very short time and most of the 6.4 seconds is waiting for the control to return
Changing the time from 90 to 900 the time is given almost but it took 2:33 , which is worse than 10x the time for 10x the data.

[Szeraax]

Of note, while you are waiting those two minutes, you can actually already run other cells. Its not LOCKED.

See this other issue regarding it: #730

[jonsequitur]

Just to note, this is not specific to PowerShell:

It's also not specific to console output. The Display API exhibits the same problem.

[jhoneill]

@Szeraax I've found the biggest problem is when I have a loop and an error - I had a typo and was doing something with a 5000 data set 5000 multi line errors caused the issue. and the I couldn't get control back in other cells, nor could I save my notebook I had to restart VS Code.

In the past I have thought I have seen variations of #730 in other places, but on closer examination it's been different.

@jonsequitur it seems to be the number of calls to [Microsoft.DotNet.Interactive.Kernel]::display() that is the issue

Changing the number of calls with this for ($i = 1; $i -lt 10 ; $i++) {$null = [Microsoft.DotNet.Interactive.Kernel]::display("", 'text/plain')}

backs up the chart @Szeraax posted on #730

dir -Recurse | out-string Outputs one large string and takes 0.1s ; without the out-string the directory I tried 20 took seconds to output 240 objects.

Previously I used out-String -width a lot I found you could over-ride the narrow width used by default with
$host.ui.rawui.set_WindowSize( ([System.Management.Automation.Host.Size]::new(175,50))
And my reduced use of out-string is probably why this problem is hitting me now.

[eosfor]

Another example

measure-command {get-process}
Get-Process

The first command was completed in just 11 milliseconds. But the whole cell does not stop even after 5 minutes. And there is no way to stop it. When you hit stop nothing happens.