"Building assets search index" is melting CPUs

Unity Engine
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1

Every time the ‘Building assets search index’ process runs, my CPU usage spikes to nearly 100% and my fans ramp up significantly.

Is there any way to optimize this process or limit its resource consumption to prevent this behavior?

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2

Which version of unity are you using? I suppose it it 6.3. Merging the indices is done in a thread and shouldn’t affect the main thread of the editor. That said: if your project is big, it means a LOT of files are read, processed and combine in a an Index Database. So this process is heavy on CPU time. We do not have a way to “slow down” this process to make it friendlier to CPU.

In 6.5 though the whole Index processing system has been redone. It is more “incremental” and shouldn’t be as brutal for CPU.

Thanks for your feedback,

Seb

3

Thanks for you reply!

I’m using Unity 6.3.11f1

It does seem to affect the main thread, resulting in some hiccups, but that’s not my primary concern. The main issue is that “Building assets search index” causes my CPU usage to spike so high that my fans go into overdrive (very loud).

Perhaps the indexing process could be throttled or given a lower thread priority to prevent it from consuming 100% of the available resources?

4

Hi @Peter77 ,

OK I understand better:

  • Basically the issue is NOT hiccup (though I understand it is annoying) but mostly power usage. I will check what we can do about this. Maybe we can lower the thread priority.
  • As for the hiccup it might be related to the main editor ui thread merging data into our IndexDb. It should be performed mostly in a thread but some synchronization is happening on the main thread.

Thanks for the feedback,

Seb

5

Hey @Peter77 ,

just for the sake of it I suggest you check your project Settings → Editor → Asset Pipeline

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This will determine how many instances of Asset worker are available for indexing (and for importing assets as well). Keep in mind that each Asset worker is in fact a batch Unity Process (unity.exe). So these can pile up up rapidly and degrade performance if you have too many instances running at the same time.

Since I work mostly on small-mid project I use 6 importer. But I know some of my colleagues with slower machine or working on way bigger project that will use as few as a single (1) worker.

Hope this helps.

Seb

6

Thanks for your reply! I’ve checked the Asset Pipeline setting and it used a higher number of desired import workers. I have now reduced it from 12 to 6 and will keep an eye whether it makes a difference.

I also noticed I use “Parallel Import” while it’s deactivated in your screenshot. Perhaps that’s also somewhat related?

My old configuration:

{086DCB71-2199-42BB-A2E4-861E58E993BF}
{086DCB71-2199-42BB-A2E4-861E58E993BF}675×298 15.1 KB

7

I am unsure what Parallel import is (this is some AssetDatabase specific settings). But it could have an impact.

If you feel your computer burning, decrease the amount of workers.

Thanks for your patience an understanding,

Seb

8

Can I assume a ‘worker’ is a full CPU thread in this case? So the maximum of workers is the maximum amount of hyperthreaded cores of the CPU?

9

How well does your 3900X hold up while doing this at 100% ? Do you notice this while tabbing to other progras while working the load?