On 06/10/2011 04:45 AM, Wen Congyang wrote:
=== 3 === Besides the above issues, I would like to open a discussion on what the libvirt API for enabling cpu hardlimits should look like. Here is what I was thinking:
Two additional scheduler parameters (based on the names given in the cgroup fs) will be recognized for qemu domains: 'cfs_period' and 'cfs_quota'. These can use the existing virDomain[Get|Set]SchedulerParameters() API. The Domain XML schema would be updated to permit the following:
--- snip --- <cputune> ... <cfs_period>1000000</cfs_period> <cfs_quota>500000</cfs_quota> </cputune> --- snip ---
I don't think 'cfs_' should be in the names here. These absolute limits on CPU time could easily be applicable to non-CFS schedulars or non-Linux hypervisors.
Do you mean the element's name should be period and quota?
The name of the file provided by cfs bandwidth is:cpu.cfs_period_us and cpu.cfs_quota_us.
I think he uses 'cfs_' because it's similar as the filename. But I do not mind the element's name.
I am making the patch, so I want to know which element's name should be used.
I think it's a good idea to use 'period' and 'quota'. In my other email I suggest that the unit for period should be microseconds and quota should be a percentage of the period. That way quota can be used without needing to know or change the default period. Please Cc: me on your patch. We are very interested in this feature and would like to review/test it. -- Adam Litke IBM Linux Technology Center