Messages in this thread |  | | Subject | Re: [PATCH V3 00/11] block-throttle: add .high limit | From | Paolo Valente <> | Date | Tue, 4 Oct 2016 21:02:47 +0200 |
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> Il giorno 04 ott 2016, alle ore 20:54, Tejun Heo <tj@kernel.org> ha scritto: > > Hello, Paolo. > > On Tue, Oct 04, 2016 at 07:43:48PM +0200, Paolo Valente wrote: >>> I don't think IO bandwidth does not matter. The problem is bandwidth can't >>> measure IO cost. For example, you can't say 8k IO costs 2x IO resource than 4k >>> IO. >> >> For what goal do you need to be able to say this, once you succeeded >> in guaranteeing bandwidth and low latency to each >> process/client/group/node/user? > > For resource partitioning mostly. It's not a single user or purpose > use case. The same device gets shared across unrelated workloads and > we need to guarantee differing levels of quality of service to each > regardless of the specifics of workload.
That's exactly what BFQ has succeeded in doing in all the tests devised so far. Can you give me a concrete example for which I can try with BFQ and with any other mechanism you deem better. If you are right, numbers will just make your point.
Thanks, Paolo
> We actually need to be able > to control IO resources. >
> Thanks. > > -- > tejun
-- Paolo Valente Algogroup Dipartimento di Scienze Fisiche, Informatiche e Matematiche Via Campi 213/B 41125 Modena - Italy http://algogroup.unimore.it/people/paolo/
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