Single CoreWebView2Environment object uses more memory than multiple CoreWebView2Environment objects

[JaseRandall]

I'm clearly wrong here but I was expecting a single instance of CoreWebView2Environment shared across multiple WebView2 instances would use less memory however I've found the opposite. eg 200mb when CoreWebView2Environment shared across four instances of WebView2 vs 150mb when four instances of WebView2 each create their own CoreWebView2Environment.

The documentation: https://docs.microsoft.com/en-us/dotnet/api/microsoft.web.webview2.core.corewebview2environment?view=webview2-dotnet-1.0.902.49 doesn't give any great insight into what's going on.

Can you please advise if it's preferable/beneficial to use a single CoreWebView2Environment shared across all WebView2 instances in my code or should I save memory and just let WebView create a new CoreWebView2Environment automatically every time I create a new WebView2 object?
Or at least, can you please point me to somewhere where I can learn myself?

Thanks in advance.
P.S. Thanks also for the work your doing on this new control.

AB#35958409

[champnic]

Thanks for the question @JaseRandall! This is certainly a surprise to me - it's possible it could be due to specific sites you navigated to. Is this reproduceable if you try it multiple times? @LiangTheDev any idea what's going on here?

[JaseRandall]

I've run some more tests using this page as the test page across 10 instances of WebView2 running in different tabs.

I see more or less the same memory usage when re-using the same environment from the first WebView2 which is creating it's own environment.

However, when I create an environment:
readonly static CoreWebView2Environment CoreWebView2Environment = CoreWebView2Environment.CreateAsync(userDataFolder: Path.Combine(Path.GetTempPath(), "WebView2 Test")).Result;

and use that same environment in all 10 instances of WebView2
new WebView2Fixed(uri, CoreWebView2Environment)

the usage is about 48mb higher.

I bumped it up to 20 WebView2 instances and the difference was about 90mb.

[champnic]

Thanks for confirming! I've changed this to be a bug and opened it on our backlog.

[LiangTheDev]

We don't expect using the same or different environment objects to impact memory usage in the WebView2 processes. The timing pattern of WebView creation and navigation might matter though. When WebViews are all created/navigated at the same time, we the code might rash to complete those operations and delay garbage collections and therefore causes memory usage appears high.
Are the timing pattern the same for the 2 tests? What happens if we wait a while or make some WebView invisible (which would trigger some cache purge).

[JaseRandall]

Hi @LiangTheDev,

The timing pattern of WebView creation and navigation might matter though.

The timing patterns were exactly the same.

What happens if we wait a while or make some WebView invisible

I waited until the memory had dropped and settled before taking the screenshots posted above. There is only a single instance of WebView2 visible at any given time. In terms of the instance that is visible, I tried hiding and unhiding it but the memory usage didn't change.

While I can save memory usage by letting WebView2 create it's own environment, I just find it odd that letting multiple instances of WebView2 create their own environment would use more memory than manually creating a single instance of CoreWebView2Environment and passing it to all the instances of WebView2.