Slow Internet / WiFi - Check discoveryd process

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Slow Internet / WiFi - Check discoveryd process

I'd like to see just how many people are having this issue because I think Apple may be looking in the wrong place to solve many folks connectivity issues.

Apparently Yosemite introduced a new way to hand DNS, which the way that computers turn names like www.yahoo.com into IP addresses. If there's a problem with DNS, it will look like your internet is slow or down when in reality it just can't resolve the IP address.

If you open Activity Monitor and look for a process called discoveryd, check out it's CPU and Memory usage. When you first reboot it uses 0.1% CPU and less than 100KB or memory.

After simply idling overnight, when I checked this morning it is now at 5% CPU usage and 240 MB of memory...the second most use of memory on my system when no apps are loaded.

One other thing you can check...while having the Activity Monitor running, open a new Safari window and go to a website that has lots of Ads or just content modules, weather.com, cnn.com, both work fine.

Watch your CPU usage for discoveryd. On my system, upon reboot, usage remains low around 1-7%. However, after running for a few hours, loading those same websites causes discoveryd to use 90-101% of CPU.

When this happens, there are also often lots, i.e., hundreds of discoveryd error messages in console. You can look at your console by simply running console.app via spotlight.

I'm not sure what to do here...I've talked with Apple engineering but that is an indirect process via customer service folks and hasn't led to any breakthroughs. I had hoped that 10.10.1 would fix the issue, but it has not.

It seems the more pages you go to, the faster this issue arrises...very frustrating.

I have tried this with a completely fresh install of Yosemite across two different iMacs including a brand new 5k Retina iMac. Same issue!! :-/

All thoughts are welcome...

iMac (Retina 5K, 27-inch, Late 2014), OS X Yosemite (10.10), Updated to 10.10.1

Posted on Nov 18, 2014 9:26 AM

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Answer 1

rwross1776 Author

Level 1

59 points

Nov 18, 2014 9:44 AM in response to rwross1776

Here's a screen shot from my console...awesome...huh?

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Answer 2

rwross1776 Author

Level 1

59 points

Nov 19, 2014 11:45 AM in response to rwross1776

bump

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Answer 3

Nov 21, 2014 8:01 AM in response to rwross1776

Same issue here. In fact, it happens several times a day. When I'm lucky, I am able to force quit discoveryd and internet(dns) starts working again... Was hoping the recent 10.10.1 release would resolve this, but no dice.

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Answer 4

rwross1776 Author

Level 1

59 points

Nov 21, 2014 10:03 AM in response to whyispickingausernamesohard

I don't know if you have multiple Apple devices on your network, but I found that quitting the discoveryd process from Activity Monitor stops my iMac from being seen on the network. I don't think the .local broadcast is restarted when the rest of discoveryd is restarted. :-(

Not a big deal if you don't have another Mac or TV on your network, but if you do, I'd suspect your iMac will no longer be visible, for example, in the shared sidebar of finder.

As for the root cause...do you have any particular apps running all the time that might be using DNS?

For example, I had a newsreader app running that regularly polled for new news..I've removed it and am waiting to see if that has some effect...

I'm starting to think that the bug in discoveryd manifests most acutely when lots of calls to DNS occurs. You can rapidly travel to many websites and see the resource usage climb on the process or have a newsreader set to poll many RSS feeds every few mins.

Any of this ring a bell for you?

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Answer 5

rwross1776 Author

Level 1

59 points

Nov 22, 2014 9:52 AM in response to rwross1776

*Update*

By reducing the number of apps that I had running in background making DNS calls, this last reboot lasted about 48 hours before discoveryd started blowing lots of console errors. For the most part, this occurred by repeated use of Safari although I'm sure some other aspects of the system were making DNS calls as well.

Memory and CPU usage never went above 50MB and 9% respectively. CPU usage settled down after I stopped actively surfing pages so, strictly speaking, a reboot wasn't required this last time since had I not been checking logs, i wouldn't have been aware of the errors.

I'm going to let the system work and see what happens this time...if it's the same as above, then I'll reboot once the errors start and reintroduce those Apps and see if things go casters up faster and with more effect.

I'd encourage everyone to get an active case going with a Senior Apple Tech and Engineering...if they start seeing those console logs coming from multiple places, it might get more focus than would otherwise.

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