[ovs-dev] [OVN Patch] Make changes to the parallel processing API to allow pool sizing

Anton Ivanov anton.ivanov at cambridgegreys.com
Fri Sep 3 09:59:02 UTC 2021


On 03/09/2021 08:56, Dumitru Ceara wrote:
> On 9/2/21 10:20 PM, Numan Siddique wrote:\
>
> [...]
>
>>> Can we have some suggestions for option names please?
>>
>> How about num_parallel_workers ?
>>
>> So user/CMS has to set 2 options (unfortunately)
>>
>> use_parallel_build=true
>> num_parallel_workers=6
>>
>> Or we can deprecate 'use_parallel_build' and use
>> 'num_parallel_workers' instead as you suggested.
>>
>> This can be a string/integer.
>>
>> i.e num_parallel_workers=auto  will enable parallel processing and use
>> the system default pool size.
>> num_parallel_workers=0  -> will disable parallel processing (this will
>> be the default value if not defined by user)
>> num_parallel_workers = N where N > 0 enable parallel processing with pool size.
>>
>> and still honor 'use_parallel_build' if 'num_parallel_workers' is not
>> set.  Does this sound good ?
> I wonder if it's better however if we don't make 'num_parallel_workers'
> a persistent config value and let the CMS pass it as a command line
> argument to ovn-northd.
>
> I'm thinking of the case when different ovn-northd instances, connecting
> to the same NB DB, run on different nodes of a heterogeneous cluster
> (with different hardware specs for the nodes running northd).
> Configuring all of them to run with the same number of threads is
> inefficient.
>
> Another point is that whenever debugging offline a NB database from a
> deployment with parallelization enabled, we'll have to first somehow
> adapt the number of threads ovn-northd would use.
>
> Thoughts?

Fair points.

Changing them at runtime would need to be a cli command instead of a config option.

A.

>> We need to document this in ovn-nb.8.xml.
>>
>> Thanks
>> Numan
>>
> Regards,
> Dumitru
>
>
-- 
Anton R. Ivanov
Cambridgegreys Limited. Registered in England. Company Number 10273661
https://www.cambridgegreys.com/



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