Profiling Question - How to find the culprit?

Development Audio
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1

Hi,
Ive been getting some lag in my game and am learning how to profile performance issues…
So I recorded a profile, and in Session Frontend I see this:

55703-profilingaudiolag.png

All other threads seem to be running CPU Stalls, waiting for this Audio Update to complete, so I take it there’s something wrong with either the audio assets I’m using or the way I’m using them.

Now my question is, how do I track down the exact function/asset that is causing this lag?
Is there a function that will take me directly to the culprit, or do I have to start selectively disabling things until the lag disappears?

2

Do you have AMD CPU ?

3

Yes AMD FX-8320

4

Check this:

especially at @aaronmcleran comment.

5

Okay, so my audio lag spikes are a problem the engine has with AMD CPUs.
My problem now is that I am not too experienced at programming and know very little about audio programming (I have been mainly working in blueprints).
I’ve done more digging in my project and the lag seems to be caused by ‘Play Sound at Location’ nodes, so I take it the problem occurs when the sound is ultimately destroyed by the engine?

Have you been able to solve the lag spikes for yourself?
Also, that link to github by aaronmcleran is broken - error 404.

I guess the next step is to transition to a c++ based project?
What do I do from there to fix this?

Thanks for helping!

6

If you can’t recompile the engine sources from the github, you should wait patiently for the next engine release with this fix.

7

Do you know if the fix is planned for any upcoming releases?
If it only gets fixed by 4.10, 4.11 or later this could seriously mess with my development plans.

Considering that, it wouldn’t be a big problem to look into compiling from github, I’ve just stuck with the binary release because I didn’t see the need to compile the engine myself so far, I thought I’d go as far as I can without spending much time in the engine’s code.

So if there is a fix I can get then I’ll do that.

8

Also, would a seperate sound card perhaps resolve the issue during developement?

9

Don’t know when

Also, would a seperate sound card perhaps resolve the issue during developement?

You can try but I don’t think so. From my research the issue is related to AMD processors not to sound card.

10

Do you still have a working link to the github fix for me please?

11

This link is good, but you need to have github account with connection to epic repo.

12

Oh okay, I see. Then I’ll try get that sorted out soon.

Thank you so much for all your help!!!

13

So the audio performance issue I had when posting this thread has been resolved in 4.9.

But if anyone finds this post in the future, here’s a great video on profiling:

“Unreal Engine Support – Rendering Best Practices – Live from Epic HQ”