[Solved] BT HH5A: Again reduced speed

i've been using a HH5A for a few years, until last weekend with 21.02.
At the beginning there were the usual problems to get the maximum WAN-LAN speed, but for the last 2 years or so i had about 100 MBit/s troughput on a Telekom VDSL line.
I just switched to 22.03 and now the troughput dropped to about 70 MBit/s. Is it because of the new firewall, the switch to DSA or are just the usual tweaks for the HH5A missing?
The DSL data rate shown by DSL Status is still 104/44 MBit/s, as it was with 21.02.
Has anybody a good idea how i can get back the missing 30 MBit/s?

Thanks in advance.

I never got my HH5A operate as router at those speeds (but likely caused by my desire to run sqm on the wan link). But just operating as bridged-modem with a 116/7.37 Mbps sync maxes out one CPU almost fully during bidirectionally saturating loads, so there will not be many reserves for other duties.

Rebooting the bthub5 for the firmware update might have (wrongly) signaled to the ISP that the line is unstable, causing them to drop the connection speed. At least my pervious ISP did exactly that after each modem reboot (new firmware, power loss/ blown fuse, etc.), it took them close to a week to ramp up the speed again.

But then would the reported sync not also change?

Yes, -6-10 MBit/s (DTAG, 100/40 (effecitively 96/34) MBit/s).

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I just checked the cpu load with htop on 22.03.0 while downloading 100MB from a fast server. While core 0 was at 99%, core 1 just idled at 5-6% resulting in a download speed of approx. 70Mb/s.
Then i enabled 'packet steering across all CPUs', which was disabled on default. Now core 1 had a heavier load, but that didn't reduced the load on core 0 and did nothing for the download speed.
Then i switched back to 21.02.03, just for comparison.
Now i got about 90% load on core 0, but again only less than 10% on core 1.
But i reached a download speed of approx. 105 Mb/s.
Toggling 'packet steering' made no visible difference.

Just like moeller0 suggested, 100 Mb/s from wan to lan (probably also vice versa) just seems to be the maximum a single core can cope with.
I'd hoped, that smp might stretch this final frontier (pun intended) a bit. That seems not to be the case.
Well, maybe some people much brighter than me may find a solution in the near future.
Now the question is, what's more important: a higher download rate or using a newer, hopefully better release.

If you're on a Vectoring enabled connection, 22.03 (with a vectoring xDSL blob) has significant advantages as there are changes to improve handling of the vectoring signals. There have also been a number of improvements to various parts of the networking support, however there are still issues with various interrupts going only to CPU 0 even if the SMP affinity is set to for those interrupts to be processed by either CPU. The only way around this is to set the CPU affinity to a specific CPU for high volume interrupts - there's a specific thread for this topic, I suggest reviewing it starting with this post.

Note that there is a patch not yet in OpenWrt which enables the second CPU to process all interrupts rather than just some (especially the ethernet tx/rx interrupts), mentioned here and there's a different patch with the same effect mentioned here but you'd have to build OpenWrt yourself to include either of these patches.

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Thank you for the additional informations.
I tried a few minor tests with 21.02.3 and 22.03.0 (which is quite difficult when you're tinkering with the only working router in the house, without any backup router and late at night when no one else needs it).
Both kernel from 21.02.03 and 22.03.0 does (still) not contain the necessary patch. So i have to do it by myself...sigh.
So to not to endager my life, i need at first another router either as immediate or permanent replacement for the HH5A or just for building and applying the patch.
Then i have to dive into "how to create your own image from the sources".
This might take a week or 10...work and family need some time, too...


While i'm waiting for the new router to arrive (it's a Plusnet One, but that's just a rebadged HH5A), i managed to set up the buildchain. After loads of trials and errors i got an image, but i'm not brave enough to flash it to my only working router. So i'll have to wait until the replacement is up and running on 21.02.
Well, maybe next week...the Royal Mail might need some more time, then there's the customs and the german delivery service also needs some days...

I've got a pair of HH5's still. both have I think 19 openwrt on. in the UK btw.

Thanks for the offer, but i received the parcel on saturday.
I think the Plusnet One looks nicer than the HH5A, but YMMV.
In the mean time i managed it to put 21.02.3 on it, and it runs fine.
So now i could flash the old router with my self-created image...and after the reboot there was no LuCI. I forgot to put it on the list of necessary packages. :face_with_peeking_eye:
I even managed to patch the source so i could use both VPEs,
but with 22.03 the vdsl download speed is still much slower compared to 21.02.3.
Maybe (with the combined knowledge of others) we'll find a solution.


It's been a while,
but it seems there's no easy way to make the HH5A with 22.03 as fast as with 21.02.
I decided to switch to a Fritz!Box 7520 (which is basically the same as the 7530), currently running an snapshot by @wilsonyan.
In my opinion, it has got enough power for the next 3 major releases :slightly_smiling_face:
So, the HH5A is put out of work and into indefinite hiatus.

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