> Il giorno 04 ott 2016, alle ore 20:54, Tejun Heo <tj@xxxxxxxxxx> 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/ -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
