5.5.1f (855646) Not Fixed - UnityWebReqest high CPU use

Asset & Content Management
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From 5.5.1f patch notes:

  • UnityWebRequest: Fixed the issue of a request continuing execution after exiting playmode, resulting in high CPU usage. (855646)

This is not fixed. It simply happens slightly less often.

Starting and stopping a scene with an asset bundle download several times will reliably bring CPU use to 100% and eventually crash the editor.

2 Likes
2

Additional: I was able to also get editor CPU use to 100% using a WWW request to pull down the same asset bundle.

Seems like it might be an asset bundle download / parse issue, maybe happening when play is stopped while the download is still in progress.

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Additional #2: This is not limited to the editor. It happens in live deployed clients on Windows and Android.

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We’re getting this on Windows and Mac editors, (repro’d on both 5.5.0p4, 5.5.1f1), haven’t confirmed for our client targets yet. (Although now I’m pretty worried and will have to confirm shortly.)

We don’t use Asset Bundles, FWIW, just downloading loose, remote JPGs into the local file system, and then later loading from there, both operations done with UnityWebRequest.

Turns my Macbook into a cooktop, only way i can fix is by completely restarting the Editor… pretty frustrating.

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Could you file a bug report so it can be reinvestigated please?

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I’m not sure what more we can add by re-filing; it’s the same bug, with same steps to reproduce: UnityWebRequest → Try Get Asset Bundle → 100% CPU Use. UnityWebRequest continues to be unusable.

This is at least the third time in as many updates a critical issue has been closed that wasn’t fixed. There might be a systemic QA problem that needs investigation.

If I can find the time I’ll submit a bug report later this week…

1 Like
7

This: “There might be a systemic QA problem that needs investigation.”

Guys I really want to be constructive but you have something going on with your QA process. I’m constantly seeing bugs “Fixed” only to see the fixes just create new issues. A great example is if you look at Global fog over the past x versions of the engine, its been fixed in one situation to be freshly broke in another. These bugs are often just "use feature A + feature B in blank scene, they are not obscure issues. Probably worthwhile to look into your processes.

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Someone filed a new ticket a clean repro project: Unity Issue Tracker - High CPU usage after playing scene when UnityWebRequest.Send() and isDone() were used in loop
(Thank you, mystery dev!)

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5.5.2p1 seems to resolve MY instances of this bug with the Editor on macOS, but I can’t speak for the other users / cases.