Re: [Qemu-devel] [v2 2/2] migration: Implement multiple compression threads

[Li, Liang Z]

>>  #
>>  # Since: 1.2
>>  ##
>>  { 'enum': 'MigrationCapability',
>> -  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks'] 
>> }
>> +  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', 
>>+ 'compress'] }
>> 
>
>I'll repeat what I said on v1 (but this time, with some links to back it up :)
>
>We really need to avoid a proliferation of new commands, two per tunable does 
>not scale well.  I think now is the time to implement my earlier suggestion at 
>making MigrationCapability become THE resource for tunables:
>
>https://lists.gnu.org/archive/html/qemu-devel/2014-03/msg02274.html

Hi Eric,

     I tried to follow your suggestion to implement a back-compat method to 
reuse the 'migrate-set-capabilities' and 'query-migrate-capabilities' , I found 
that I should change a lot of current code to make it work, and I don’t know 
how to deal with the HMP interface.  So I add 'migrate-set-parameter' and 
'query-migrate-parameter' interface to reduce the migrate-tunable commands, 
they can deal with all the 'int'  type parameter, now the ' compress-threads' ' 
, 'decompress-threads', and 'compress-level' and be set/queried with the two 
interfaces. 

{ 'enum': 'MigrationParameter',
  'data': ['compress-level', 'compress-threads', 'decompress-threads'] }

{ 'type': 'MigrationParameterStatus',
  'data': { 'parameter' : 'MigrationParameter', 'value' : 'int' } }

   I am not sure if it's a good solution, but it's much more simple, and it can 
minimize the change of current code. Is that OK?

Liang