Bug 420113 - Skrooge very slow without ::1 set as ipv6 address
Summary: Skrooge very slow without ::1 set as ipv6 address
Status: RESOLVED LATER
Alias: None
Product: skrooge
Classification: Applications
Component: general (show other bugs)
Version: 2.18.0
Platform: Debian testing Linux
: NOR minor
Target Milestone: 25.1.0
Assignee: Stephane MANKOWSKI
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-04-15 12:07 UTC by pat_h
Modified: 2020-11-28 17:13 UTC (History)
1 user (show)

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Description pat_h 2020-04-15 12:07:24 UTC
SUMMARY


STEPS TO REPRODUCE
1. ip addr delete ::1/128 dev lo
2. start skrooge
3. stop skrooke
4. ip addr add ::1/128 dev lo
5. start skrooge

OBSERVED RESULT
The first time skrooge is started it is very slow (start-up time of few minutes instead of seconds).

If the IPv6 stack is completely disabled (ipv6.disable=1 as kernel parameter) or partially disabled (echo 1 | tee /proc/sys/net/ipv6/conf/{lo,all,default}/disable_ipv6) or the IPv6 link local address is set, startup is fast.

EXPECTED RESULT
Always fast startup independent of used IP addresses.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
The missing link local address was not on purpose, so finding the root cause fixed this bug for me. Although it would probably be better to not depend on an IPv6 link local address, the important thing is to document this behavior (which this bug report does, at least to some extent).
Comment 1 Stephane MANKOWSKI 2020-04-25 14:43:54 UTC
Hi,

I'm not a network specialist and I don't know how to reproduce this issue to try to fix it.
My distribution is KDE Neon (based on ubuntu).

Do you know how I can reproduce this issue?
I tried this:
sudo ip addr delete ::1/128 dev lo
skrooge

But Skrooge starts normally (no performance issue).

Thank you in advance if you can help me.
Regards.
Comment 2 pat_h 2020-04-25 15:42:00 UTC
Hi,

what you did triggers it here (just reconfirmed). Unfortunately, I do not have any idea how you could reproduce it besides this way. I am on Debian testing on a 5.5 kernel, which should be close to what KDE Neon provides.

Thanks a lot for your effort, but honestly I guess there is more important work than fixing this bug, as it seems to be non-reproducible on other systems and after adding ::1/128 it's neither a problem here. So all in all no one has an issue. So I am totally fine if you close the report.

Kind regards
Patrick