[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Bug#1022170: marked as done (Excessive network latency with PREEMPT_RT)

Your message dated Thu, 01 May 2025 17:14:27 +0200 (CEST)
with message-id <20250501151427.20807BE2DE0@eldamar.lan>
and subject line Closing this bug (BTS maintenance for src:linux bugs)
has caused the Debian Bug report #1022170,
regarding Excessive network latency with PREEMPT_RT
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
1022170: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1022170
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message ---
Package: PREEMPT_RT 
Version: 5.10 to 6.0

I am writing on behalf of the linuxcnc community who require the PREEMPT_RT real time kernel.

Linuxcnc is now  packaged in Debian..

Users have found that there is excessive latency on network interfaces in kernels 5.10 and above when using Realtek NIC's. ( I have used most kernels 5.10  to 6.10)
Linuxcnc is a real time application and is dependent on a 1 ms servo thread (eg timer interrupt thread).

Many users use motion interfaces that use an ethernet connection to the host PC. When excessive NIC latency occurs, the strict timing we require is violated and we receive an "error finishing read" which disables the motion interface. eg. Insufficient time remains to do what we require in a real time setting.

Hard Kernel, the manufacturers of the Odroid H2 and H3 range of SBC's who use a 2.5 gb Realtek RT8125 report that the Linux kernel drivers are 15-30% slower than the genuine  Realtek driver which can be downloaded and compiled from source. Ref:  https://wiki.odroid.com/odroid-h3/hardware/install_ethernet_driver_on_h3plus
The Odroid is an ideal SBC to install Linuxcnc on.

Now that Linuxcnc is packaged in the Debian 12 repos, a resolution of this issue is required. I appreciate that this issue may need to be escalated to the kernel developers. Please note that I am a user not a linuxcnc developer.

I am seeking guidance on how to resolve or escalate this issue..

--- End Message ---
--- Begin Message --- 
Hi

This bug was filed for a (very) old kernel or the bug is old itself
without resolution. Maybe it was for a feature enablement which nobody
acted on. We are sorry we were not able to timely deal with this issue.
There are many open bugs for the src:linux package and thus we are
closing older bugs where it's unclear if they still occur in newer
versions and are still relevant to the reporter. For an overview see:
https://bugs.debian.org/src:linux .

If you can reproduce your issue with

- the current version in unstable/testing
- the latest kernel from backports

or, if it was a feature addition/wishlist and still consider it
relevant, then:

Please reopen the bug, see https://www.debian.org/Bugs/server-control
for details.

Please try to provide as much fresh details including kernel logs where
relevant. In particular were an issue is coupled with specific hardware we
might ask you to do additional debugging on your side as the owner of the
hardware.

Regards,
Salvatore

--- End Message ---
Reply to: