Xrx200 IRQ balancing between VPEs

I assume i have to select perf and perf_event in the kernel menuconfig? Well, i didn't found it :frowning:

Maybe you can give me some more help where and what to select? I really would like to give you the informations you asked for, but i'm unable to configure the build myself...it's just overwhelming.


Global build settings --> Kernel build options --> Compile the kernel with performance events and counters
Development --> Perf

On "Kernel build options" i can't find an entry for "Compile the Development", and therefore no sub-entry for "Perf".
Or is this only valid for the 5.15 kernel?

Development --> Perf (second line) are in the main menu. These options should only appear when you enable perf_event (first line). Both options are definitely available on kernel 5.10.

1 Like

Oops...my mistake. There's a difference between 'reading a text' and 'understand what it means' :face_with_peeking_eye:
Please blame my work for it...
Finally i found the entries and enabled them.
Now it takes some time on this old PC to compile the whole image.

Thank you.

1 Like

It's up and running, but i can't upload the .svg file because it's a not authorized file format.

Send me these files via email. My email address: olek2 at wp.pl

do you already had some time to take a look on the files i sent you?

Or maybe already found a solution to make the HH5A with 22.03 as fast as with 21.02?

1 Like

I got the email, but have not yet identified the problem. Can you generate the same graphs for OpenWRT 21.02? This will make it easier to identify the problem.

I also wonder if this problem is specific to Lantiq. It is difficult to compare performance on this targe because random code changes can reduce performance by 25%. This is probably due to the alignment of hot loops or functions to cacheline.

A performance loss or gain by 25% is quite a lot, especially when the device hasn't got much resources left.
The improvements in 22.03 may take their toll, so the HH5A might be just at the limit while 'only' using PPPOE and routing/firewalling.
At the moment i'm trying to get a used Fritzbox 7520 (which is identical with the 7530, with some restrictions done in the firmware) at a reasonable price.
But since a few weeks the prices go up, and (super)vectoring capable hardware becomes more expensive.
Maybe i'll try to use one HH5A as a bridged modem and the other as a router, but that will double the power consumption and raise the cost...

So as bridged modem my HH5A consumes something like 6.9 W on average (see here) (both WiFi radios disabled).
In my limited experience the HH5A (in 2018 IIRC) did already struggle on a 50/10 link with NAT, firewall, SQM, WiFi, speedtests over WiFi stayed well below the expected throughput. I reluctantly relegated it to bridged-modem duty, which it now does satisfactorily on a nominal 100/40 link (VDSL2/PTM sync 116.797 Mb/s / 36.999 Mb/s, full bidirectional throughput is a bit behind the theoretical limit, but fast enough for me not to bother, YMMV).

Well, we know that SQM consumes quite a lot of power.
I assume, when somebody wants to use SQM / CAKE you need a device that has to be much more powerful than this rather cheap wifi router.

While my HH5A 'only' does PPPoE and routing/firewalling, i had no problems using the full DL/UL speed with 21.02. Of course with a cpu load of about 95%.
This changed when i ugraded to 22.03. The maximum is at approx. 85 MBit and the cpu on 99%.
I guess it's like with many software: newer versions may be faster or have got additional functions, but they need stronger hardware to accomplish this.

Until oleg210 or any other genius finds a solution to keep the speed on 22.03, i'll be using 21.02.5.

Unfortunately there's no alternative to Lantiq. Broadcom and Qualcomm modem chips might be better, but without available drivers they will never be supported by OpenWRT.

Well, just as reference my wndr3700v2 of similar vintage had no problems with all of this (modulo the DSL) at 50/10. My point is that HH5A really is not a high performance platform, and as attractive a single all-in-one router is, the HH5A only cuts it for low speeds IMHO.

That is as understandable as it is risky. Mind you for a bridged-modem where to control GUI is not reachable over the internet running an old version is IMHO less critical than for a primary router.

True, but there are slightly more modern lantiq SoCs that are supported with a few additional patches like the vrx518 that are not as old as the xrx200 in the HH5A. I have no direct experience how well something like a fritzbox 7530 will actuall di as all-in-one dsl router though, but I expect the 4 core ARM cpu to be a tad better than the HH5A's.

I agree with you, this box is a budget router. But with 21.03 it was fast enough for my (our) purpose.

That's for sure.
I do hope, 21.03.5 is safe enough for the moment.
On the other hand, when i think about the millions of ISP-routers with their outdated, sometimes even critical firmware i get the creeps.

Well then, a used Fritzbox 7520 is on its way. The image is already built, i'm eager to see how much resources will be left over with 22.03 on this box.

I made this build if you want to test, it's latest master. Just backup your current config and go for config wipe when flashing and then when going back just do a config wipe again and then restore your old config. I made this build with -march=34kc so one small drawback is a little bit of speed loss on unaccelerated openssl but other than that it should be ok to route at least 100mbits/s. Also no dsl blob is included so you'll have to 'scp -O ...' one on yourself.

Under the status menu there's a new " DSL line spectrum " section with a bunch of graphs

1 Like

Thank you.

I'll try this one on the weekend (hopefully), but for the moment i'm into the FB7520 i got today.
Just for the speed of response (especially on LuCI) i can see that this box is much faster than the HH5A.
But there may be a neighbor who would like to replace his much older router with one of my HH5A.


It's difficult to switch the router and test new builds when there's always someone in the family who needs the internet connection right now very urgent :face_with_raised_eyebrow:.

Well, now i had some time and did a quick check on your build:
The maximum download speed via VDSL w/ default configuration is approx. 7460 kByte/s.
With enabled packet steering it goes up a little bit to approx. 7770 kByte/s.
When i assign xrx200_net_rx on irq72 to VPE1 instead of VPE0 with
echo 2 > /proc/irq/72/smp_affinity
i'll get a download speed up to approx. 9900 kByte/s.
So there's no big difference compared to my build based on 22.03.0 and the official image build on 22.03.2.
It's still slower than with 21.03.5, where i can reach up to approx. 11.500 kByte/s.
I assume, OW 22.03 just needs more (cpu-)power to achieve the same results as 21.02.
But the HH5A is at its limit, and so it throttles the data throughput.
So, if anybody wants the maximum data rate with a HH5A, [s]he should stay on 21.02.

Or make a clean brake and switch to a stronger device (like i did with the Fritz!Box 7520).

Anyway, thank you for your efforts. But sorry, no cigar. :smiling_face_with_tear:

yeah I guess the ultimate trick would be to keep the old pre-dsa drivers with the patches that were released here to make it faster with the latest 5.15 kernel or something. The DSA driver is cool and all but by the time you have the hh5a running a DSA bridge and then a br-lan bridge on top of it the performance is definitely worse than just being able to have 1 br-lan bridge and use the swconfig for vlans. Though it seems like you can get around it by just making vlan devices off the individual ports to avoid having 2 bridges. Also it seems like the backported BPF mips32r2 stuff may not quite be all there for some things, I had to remove the bridger daemon because it segfaults sometimes on link up and down. I'm not sure where you get the speed limits there, as with that build I'm pretty sure I was able to download at over 10 megabytes/sec from my provider and speedtest showed about 94 megabits/sec download.

but yeah the fritz 7530/7520 devices are working great now anyway thanks to work by janh and dhewg, the extra sync rate for me alone is a lot better, it's 103.5 vs 112.

1 Like

Modem only operations are bread and butter of lantiq those days. DSA and mini jumbo frames allows to be more creative. Like using AP and network switch to expand local network while keeping modem operations on lantiq but routing and sqm on other device .
update: my FB7362SL used in this mode barely hit 40% in this monthly usage stat:
I'm also using IRQ remap ethernet and wireless to 2nd core while 1st handling VDSL operations

echo 2 > /proc/irq/144/smp_affinity
echo 2 > /proc/irq/72/smp_affinity
echo 2 > /proc/irq/73/smp_affinity