CPU Core 1 Spiking 100% GT-AX6000 other cores seems no utilized. Merlin 388.1

[JPP PPJ]

Hello,

I purchased a brand new gt-ax6000 based on feedback and a lot of in-depth tech reviews. One observation I have is that it seems software and hardware only utilize 1 core to execute QoS related tasks. As a result, Core 1 is always active and spiking to 100% when I do downloads and/or upload at 900+ Mbps. I am running Merlin 388.1. Flash 2 different times and NVRAM cleared. Same behavior with latest stock firmware.

I already disabled the radios so no WiFi, this is only a router device for routing functions. Every time I enable QoS regardless of the option selected, core 1 spikes to 100% and the remaining cores stay at 0-5%.

I am using both 2.5 Gbps ports.

Is this a normal behavior? - I am re-thinking if the router is the correct one for 2 Gbps service with QoS enabled. Thoughts?

 

[L&LD]

With 2Gbps service, you don't need QoS.

 

[John Fitzgerald]

Turn "OFF" QoS and see if you observe the same issue.

 

[jass]

Is this a normal behavior? - I am re-thinking if the router is the correct one for 2 Gbps service with QoS enabled. Thoughts?

Problably and problably not...

Asus routers are packet with a lot of great features, and even more so if you choose to run Asuswrt-Merlin on it. But there is a big but here, these features needs processing power. And the speeds you are talking about, quite a bit more than Asus currently offers...

By enabling QoS or AiProtection or quite a number of the other great features on the Asus router, you are quickly down to mayby 1/3 of advertized router speed due to it lack of processing power. That's simply the sad truth, for otherwise I just love Asuswrt/Merlin GUI and all the great features which comes with it!

If I were you, and the speed you are talking about. I'd take a look at PfSense or OpnSense and some hardware to handle what you are talking about.

 

[drinkingbird]

Hello,

I purchased a brand new gt-ax6000 based on feedback and a lot of in-depth tech reviews. One observation I have is that it seems software and hardware only utilize 1 core to execute QoS related tasks. As a result, Core 1 is always active and spiking to 100% when I do downloads and/or upload at 900+ Mbps. I am running Merlin 388.1. Flash 2 different times and NVRAM cleared. Same behavior with latest stock firmware.

I already disabled the radios so no WiFi, this is only a router device for routing functions. Every time I enable QoS regardless of the option selected, core 1 spikes to 100% and the remaining cores stay at 0-5%.

I am using both 2.5 Gbps ports.

Is this a normal behavior? - I am re-thinking if the router is the correct one for 2 Gbps service with QoS enabled. Thoughts?

Most (possibly all) of the processes on these routers are not multi-threaded, meaning they can only use 1 CPU. I believe they've tried to assign certain processes in the firmware to certain CPUs to try and balance the load, but QOS can only use one core and it is saturating that core.

As others have said, if your internet service is that fast, you don't need QOS, unless you have a slow upload speed, in which case you should be able to just apply an upload limiter. Not positive if you can do that without download also passing through QOS though.

 

[Tech9]

Is this a normal behavior?

Yes, the same behavior on other routers with multi-core CPU. All routing is done on Core 1.

 

[JPP PPJ]

I really like Asus and Merlin paired. I have been using them for many years and the only times I have picked something different is because complaints received about the aesthetic of the asus router in visible areas at home .

Main interest of the QoS is work related and constantly using the bw, of course not all the time and the piece of mind having the QoS and avoid degradation to voice/collaboration apps.

The spiking is with only routing, QoS and NAT enabled. Everything else including WiFi is disabled. I may have to wait for the new router/CPU to see if QoS can be enabled or wish routing can be multi-threaded.

 

[JPP PPJ]

Problably and problably not...

Asus routers are packet with a lot of great features, and even more so if you choose to run Asuswrt-Merlin on it. But there is a big but here, these features needs processing power. And the speeds you are talking about, quite a bit more than Asus currently offers...

By enabling QoS or AiProtection or quite a number of the other great features on the Asus router, you are quickly down to mayby 1/3 of advertized router speed due to it lack of processing power. That's simply the sad truth, for otherwise I just love Asuswrt/Merlin GUI and all the great features which comes with it!

If I were you, and the speed you are talking about. I'd take a look at PfSense or OpnSense and some hardware to handle what you are talking about.

@jass I am looking at both , pfsense and opnsense. Netgate seems more affordable. Lookin at generic hardware too. For sure like more the simplicity of asus.

 

[Tech9]

because complaints received about the aesthetic of the asus router

So this time you have decided to bring home the ugliest one as a revenge?

 

[jass]

@jass I am looking at both , pfsense and opnsense. Netgate seems more affordable. Lookin at generic hardware too. For sure like more the simplicity of asus.

One of the cool features of these two, is that it will most likely run on any old computer you have laying around... And most likely manage the job also, even though your requirements are in upper loevel. At least you get to play a little with both of them on almost any retired hw or you can set it up as a wm. That way you dont have to invest in any expensive hw before you have made up your mind...

OpnSense are most likely the easiest to start with, because of the documentation available, but both are less scary than you think once you have played a little with them...

Altough I agree with you when it comes to the simplicity and looks of Asuswrt/merlin GUI. The perfect combo would be an Asuswrt-Merlin version you could install on any hw of your choice...

Best of lucks whichever way you choose to go!

 

[drinkingbird]

One of the cool features of these two, is that it will most likely run on any old computer you have laying around... And most likely manage the job also, even though your requirements are in upper loevel. At least you get to play a little with both of them on almost any retired hw or you can set it up as a wm. That way you dont have to invest in any expensive hw before you have made up your mind...

OpnSense are most likely the easiest to start with, because of the documentation available, but both are less scary than you think once you have played a little with them...

Altough I agree with you when it comes to the simplicity and looks of Asuswrt/merlin GUI. The perfect combo would be an Asuswrt-Merlin version you could install on any hw of your choice...

Best of lucks whichever way you choose to go!

In reality, running them on a micro x86 box (or Opnsense on Raspberry Pi or other micro Linux environment) somewhat designed for this kind of purpose will likely end up saving you the cost of the box in electricity though, also save a lot of space. There are lots of setups available for "DIY IOT" stuff and they take a lot less power and can be gotten extremely small.

But yes agreed if you just want to play with it and see if fit for purpose, nice to be able to just grab some old PC and fire it up.

 

[JPP PPJ]

So this time you have decided to bring home the ugliest one as a revenge?

I can neither deny nor confirm...

 

[JPP PPJ]

Good advice and thank you all. I need to dust off my aging IT knowledge and skills. I will try pfense/opnsense on VM running on a current desktop I have with an X550 card ( yes, I am crazy running high speeds on my LAN). @jass It would be fantastic to be able to run Merlin on VM, I think is not even a dream. Thank you all again. I will report back.

 

[JPP PPJ]

@Tech9 @drinkingbird - One more question - What does Bandwidth Monitor do besides showing the traffic/bandwidth used? What does the highest, high, medium, default, lowest tags do? Does it prioritize traffic in combination with the QoS? Does it provide priority to the traffic coming the specific device and overrides the setting in the QoS sections?

 

[Tech9]

What does the highest, high, medium, default, lowest tags do?

This thing is for Traditional QoS or when you enable Device Prioritization in "Gear Accelerator" which does the same thing - enable Traditional QoS. I haven't played with this from a long time and may have some changes in 388 firmware. The GUI in Bandwidth Monitor is for sorting devices per priority, but it does noting with no QoS or Adaptive QoS. Asuswrt GUI is a little mess with remaining elements from previous firmware versions/features, the same settings named differently for marketing purposes and lack of dependencies. You may have completely contradicting features enabled at the same time and unrelated to your settings GUI elements displayed.

 

[Pocah]

With 2Gbps service, you don't need QoS.

I agree with this. You only really need QOS when there is a bottleneck. With your ISP there isn't a bottleneck. Once you get up to these sorts of speed it's a mistake to anticipate issues.

 

[DAOWAce]

Year old thread, but..

With 2Gbps service, you don't need QoS.

As others have said, if your internet service is that fast, you don't need QOS,

I agree with this. You only really need QOS when there is a bottleneck. With your ISP there isn't a bottleneck. Once you get up to these sorts of speed it's a mistake to anticipate issues.

This is not true. QoS is completely independent from how fast your network is.

QoS applies prioritization. Without QoS, if you max out your connection with a transfer, all other data gets traffic jammed. This is disastrous with latency sensitive data like games, VoIP and streaming services. Latency goes through the roof, they can hang for multiple seconds at a time.

With QoS, you can still do all these things with minimal degradation. There is still some, yes, but it's orders of magnitude lower (30-50ms increase) than without any QoS at all (7000ms).

When I upgraded from a 200/35 cable connection to 1G symmetrical fiber, I ran into the same issue as posted in this thread: Terrible network performance with QoS enabled. It didn't matter what QoS I tried using, the transfer speed was crippled. The only 'solution' was to disable QoS and run into the awful problem of not having it anymore, or deal with erratic 20-60% lower transfer speeds than I'm paying for. This is ignoring bufferbloat issues too.

Been using QoS since my first "gaming" router (D-Link DGL-4100) from 2005. I even invested into Bigfoot's Killer NIC because it provided tangible benefits over generic onboard crap (especially for UDP). I've been a competitive gamer and I also play some lockstep games, and consistent low latency is extremely important in both these cases. I also live with a family who's become more and more digitally oriented. QoS is a godsend for people like me.

Surely there's a router out there that either has a CPU powerful enough for at minimum 1G QoS, or is multi-threaded? This can't still be a bottleneck in 2024.

With how many ASUS routers have had glaring flaws (former 87U user), I'm close to not caring anymore and will even consider paying for enterprise hardware...

 

[Squall Leonhart]

With 2Gbps service, you don't need QoS.

you keep saying this, but its nonsense unless you're the only user in your home doing anything on the internet.

 

[sfx2000]

Isn't the GT-AX6000 a Qualcomm-Atheros device?

If that's the case, how can RMerlin's FW even run here?

Anyways - on a multicore device, one "core" running at 100 percent is actually 25 percent of the undivided whole on a 4-core device.

top doesn't always report the right thing... esp w/busybox.

 

[RMerlin]

Isn't the GT-AX6000 a Qualcomm-Atheros device?

No. That page has the wrong info.