Terrible Performance while Mouse Down

I'm seeing a large spike in CPU when I hold the mouse button down. It causes rendering & overhead time to increase, even though the scene's rendering complexity hasn't changed. I presume something funny is happening with the mouse raycasting, but I don't know what:



Unity Beta 5.4b22 x64, DirectX 11, Windows 10 x64. CPU spike happens when the mouse is down, and immediately clears when the mouse button returns.

I'm relatively new to Unity, so I'm not sure if there is a common pitfall that causes this behavior? Maybe this isn't happening on a full build? Any way to run a performance profile on a full build?

 

if unityUI is like my kissUI, when you want to Drag the Image, and the Mouse Leaves the Current Images area, and the Mouse Enters another images area... and in your own code, you move the image to follow the mouse cursor... it becomes a vicious cycle of Mouse Enter and Mouse Leave... So many GetComponent() calls. :/

well, I added caching of images, or am about to, of the last few images the raycast hit, just to avoid calling GetComponent if possible.
well, kissUI does have another way to avoid this, an option to Ignore raycasting other images when a specific image is Dragged. Speed!

webGL example of performance (Microsoft EDGE is fastest browser, then Chrome [when it doesn't get the Hiccups], then Firefox for me):
http://kissui.izzysoft.com/support/index.php?action=demos;sa=dragdrop501

 

Case 809888.

This is a really large issue. Imagine trying to hit 90FPS+ for Virtual Reality & the biggest problem holding you back is holding down the mouse button.

I opened up a completely blank, new project & saw large drops in performance with nothing but holding down the mouse. Something is going on wrong here. I trust you can find a solution!

 

I'm glad to report I got a notification that this bug was fixed. I'll be looking forward to the next release to test!

 

BTW why are there 11 EventSystem updates going on in a single frame ?