Messages in this thread | | | Date | Thu, 2 May 2013 11:49:53 -0700 | From | Tejun Heo <> | Subject | Re: [PATCHSET] blk-throttle: implement proper hierarchy support |
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Hello,
On Thu, May 02, 2013 at 02:45:14PM -0400, Vivek Goyal wrote: > I did not understand this point. In flat model, application issuing > at configured page will not get penalized. > > This penalty is coming from the fact that we are moving bios after the > wait and make them wait in another queue. > > In flat model there is no such problem. So to me, it is the problem > of how hierarchical scheduling is implemented. In flat model, I did > not have to deal with it.
But seen from the parent, the child isn't different from any other issuer in flat hierarchy. It's just being repeated, so if you assume a process which behaves in the exact same manner, that process would get penalized too. e.g. imagine an application which throttles itself and issues exactly 1MB/s amount of data in direct IO. It'd get penalized the same way, right?
> Ok. Not having a perfect algorithm now is fine. We can always redo it > later.
I think we can do source-based RR on bio_lists[] fetching which is simple enough and should be able to avoid most of the problems, right?
Thanks.
-- tejun
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