100% cpu usage on core 1 of AC88U

[Matteo Guglielmi]

Not sure if this helps anyone else, but when I experienced this issue - it was all I/o CPU. Ended up swapping my USB stick for another one (after cloning) and the issue was gone.

Worth a quick look to see if that’s your issue.

Will replace the usb key on all my routers and let you guys know.

 

[thecheapseats]

Just a heads up - the connectors on USB sticks, cables as well as device receptacles on hardware tend to get oxidized and dirty - even new stuff that's been sitting in packaging for a few years... a little DeoxIT spray (less is more - get a q-tip) goes a long way on these funky connectors if they are an issue... pin tolerances on consumer electronics stuff today that rely on friction-cleaning aren't exactly 'precision' any more... that DeoxIT spray has saved my butt more times than I can remember...

 

[jrowe88]

I just solved another 100% CPU issue. In my case it was "[bcmsw_rx]" that was pegging the CPU.

I have a Linux NAS and has the two gigabit ethernet ports configured for "bonding" with the "balance-rr" mode (which stands for round robin). I'm sure I set it up a while ago and that was just the default. But, as a result it would alternate packets between NICs and that would drive the the switch into apoplexy any time files were copied to and from the NAS.

Just thought I'd add this to the thread in case it helps someone down the road.

 

[index]

Also experiencing same issue.
acsd process utilizes 100% of one core.
On / Off WPS resolved the issue (Initially WPS was Off).
But not sure for how long

 

[Tecchie]

I too have been having the single core 100% usage for quite a while now, probably 8 months worth of Merlin updates. Even performed the 30-30-30 reset and ONLY setup my SSID & password (and separated my 2.4Ghz from my 5Ghz and named them appropriately.)

Here is a screenshot while running a speed test. It's large 2560x1440 But I ran the TOP command and not sure what I'm looking at here, but this speed test was ran WIRED.. WIRELESS is a different story. It will use like 66% of core 1 and a little above 20-30% for core 2, but settle out during the speed test..

Reference: Asus RT-AC3100
Connection: Comcast Gigabit service

If I re-enable the Comcast modem gateway functions and just use that only, there is no speed issues wired or wireless. But I like the control I have with my router.

Been happening since some version back to 384.xx or whatever..
Any thoughts?

This is after a fresh firmware clear (30-30-30) and a setup of Wireless SSID and ONLY enabling SSH (usually I leave it disabled)


also, long time lurker and figured since I cant seem to figure out why this is happening, I'd finally register.. lol


thanks for any input or help.

 

[Tech9]

This is after a fresh firmware clear (30-30-30)

I don't know what your issue is, but there is no 30-30-30 with Asus routers and your screenshot is impossible to read. Core 1 reaching 100% is not unusual during speed test. CPU load depends on how fast your ISP is and if the hardware acceleration is on/off. What's the issue again?

 

[Tecchie]

I don't know what your issue is, but there is no 30-30-30 with Asus routers and your screenshot is impossible to read. Core 1 reaching 100% is not unusual during speed test. CPU load depends on how fast your ISP is and if the hardware acceleration is on/off. What's the issue again?

I'm not getting my full connection speed out of my router like I used to. Wifi seems to stop working on some devices where it didn't before. And core 1 gets hammered weather or not I'm running a speed test. Core 2 rarely gets touched. even while media streaming or when the kids are on their zoom calls with school (4 of those using it at that time)

Not sure where to turn back on the hardware acceleration anymore

 

[Tecchie]

I don't know what your issue is, but there is no 30-30-30 with Asus routers and your screenshot is impossible to read. Core 1 reaching 100% is not unusual during speed test. CPU load depends on how fast your ISP is and if the hardware acceleration is on/off. What's the issue again?

Also, NAT acceleration option is only AUTO or DISABLE.. I have tried it with QOS on and off, but there is no "time scheduling" or guest network or bandwidth limiters turned on.. I haven't changed my settings for a couple of years, only been keeping firmware updated..

I used to get full line speed during a speed test over WIFI, but it's about half now.. Even when my devices are right on top of the unit

 

[Tech9]

I used to get full line speed during a speed test over WIFI, but it's about half now.. Even when my devices are right on top of the unit

Connection: Comcast Gigabit service

You can't get Gigabit speeds over Wi-Fi with this router. You can get close only with 4-stream AC client holding the maximum 1733Mbps link speed and with clear 80MHz channel. Do you have a 4-stream AC client to test with? Your hardware acceleration is Enabled, otherwise you won't see speeds over 300Mbps to any client. I don't see your CPU at 100% in top and the UI part shows the Internet Traffic meter. Core 1 does routing duties and is normal to see it jumping up and down with heavy transfers. You can see Core 2 doing the same thing if you start Samba transfers to USB attached storage. Post a picture of UI showing CPU load with the router in idle. Does Core 1 stay at 100% all the time? According to your previous attached picture - it doesn't:

 

[Tecchie]

You can't get Gigabit speeds over Wi-Fi with this router. You can get close only with 4-stream AC client holding the maximum 1733Mbps link speed and with clear 80MHz channel. Do you have a 4-stream AC client to test with? Your hardware acceleration is Enabled, otherwise you won't see speeds over 300Mbps to any client. I don't see your CPU at 100% in top and the UI part shows the Internet Traffic meter. Core 1 does routing duties and is normal to see it jumping up and down with heavy transfers. You can see Core 2 doing the same thing if you start Samba transfers to USB attached storage. Post a picture of UI showing CPU load with the router in idle. Does Core 1 stay at 100% all the time? According to your previous attached picture - it doesn't:

View attachment 33721

Fastest speed I've seen over wireless that I have recorded was 680Mbps

 

[Tech9]

Fastest speed I've seen over wireless that I have recorded was 680Mbps

It's possible. I guess, a laptop/macbook with 3-stream client. Most clients are 2-stream, you can see 480Mbps, or about half of your Gigabit ISP.

 

[Tecchie]

It's possible. I guess, a laptop/macbook with 3-stream client. Most clients are 2-stream, you can see 480Mbps, or about half of your Gigabit ISP.

I have an iPhone XS Max 512GB and a 12.9" iPad Pro which support MIMO... iPhone is 2x2, and my iPad is 2x2 with HT80.. 802.11AC

See my attached screenshot.. I only ever hit that number with the current firmware at the date/timestamp on the second image.

 

[Tech9]

Inaccurate speed test. Not physically possible with 2x2 AC client. Your maximum link rate is 866Mbps, usual throughput 50-60% of that.

 

[Tecchie]

I’ll upload the other one tomorrow, but it was 585Mbps. But also I remember why that was over 900, I used a lightning to USB3 adapter then a USB3 to Gigabit adapter..

my mistake.
However, I’m still hovering around 700-800Mbps. Bottom line, it’s still slower than being directly connected to just my modem. I should have that much loss. I used to test right at 1,000 or like 995 was my steady average hardwire testing through my router

 

[Tech9]

There is a good read here - https://www.duckware.com/tech/wifi-in-the-us.html
See the possible link speeds you can get from different Wi-Fi generations, divide roughly on half - this is what real life Wi-Fi can give you. Your Wi-Fi speeds are very good. I wouldn't rush upgrading the router. If you decide to upgrade anyway and stay with Asus, the current favorite is AX86U model. You may not see much benefits though. Can you tell the difference between 200Mbps and 400Mbps on your iPhone? Your YouTube video will load 2 seconds faster, perhaps. Your iPhone/iPad have nothing to do with Gigabit speeds. Laptops and desktops connected wirelessly may have some improvements.

 

[Tech9]

I used to test right at 1,000

Your router's Gigabit LAN ports can do about 940Mbps. Don't trust too much speed tests.

 

[Tecchie]

Your router's Gigabit LAN ports can do about 940Mbps. Don't trust too much speed tests.

In addition to all this, I’m getting WiFi connectivity issues several times a day and it requires router reboots. 3-5 times a day at least.

We have at least 15 WiFi devices and most of them are on and using the network nearly all the time.
The cut outs also affect one or more of my kid’ Zoom meetings with their classes.

 

[Tech9]

In addition to all this, I’m getting WiFi connectivity issues several times a day and it requires router reboots. 3-5 times a day at least.

Better open a new thread and describe in details the issues you have. Seems like unrelated to this thread.

 

[Tecchie]

Better open a new thread and describe in details the issues you have. Seems like unrelated to this thread.

Even though all my lan connections only peg the first core to100%? I’m not getting full speed most days when it does that

 

[Tech9]

I see 120MB/s internet traffic on one of your screenshots, post #107. What more do you expect from a 6y old home router?