nameservice.c: adjust writing files

[Akira25]

At Freifunk Berlin we experienced fairly random updates on the files. This
resulted from the calc_jitter() function in the scheduler.c.
By calling the function with a jitter of 0% there shouldn't be any randomness
anymore and the nameservice-files should get written on schedule.

Signed-off-by: Martin Hübner [email protected]

This PR is still under testing for having the desired effect. Thus draft-state for now.

[mathiashro]

@Akira25, I'm just curios ...

1. Was there may be good reason to have some back-off / non-synchronous write procedure?
2. What is the current impact on your mesh?

[Noki]

@mathiashro The impact is that we observed delays for nameservice updates of several hours even when setting filewrite_interval to 60 seconds. In general a back-off / non-synchronous write procedure can be a good idea, however random backoffs resulting in huge and undeterministic delays are obviously not.

[mathiashro]

@Noki / @Akira25, do we want to wait for further comments and community feedback or just merge it? (We may introduce also a config parameter if we do have different requirements by different OLSR users.)

For me we are fine to merge and I can finalize that. As for our mesh (Rostock) we did not had the issue with the backup yet but currently mainly try to remove our dependency on the nameservice plugin for all central services.

Proceed with merge or wait?

[Akira25]

@mathiashro I'd prefer to test this for me. Maybe forgot to make this a Draft. So I'm open to wait for some further comments.

[mathiashro]

Hi @Akira25, did had some time to test the changes in your environment?

[booo]

We have a patch laying around somewhere that sends a signal to a process as soon as there is new information on names. This could remove the regular write operation.

[Akira25]

Hi @Akira25, did had some time to test the changes in your environment?

Sadly not. Help with this is highly appreciated!