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    SubjectRe: [PATCH 01/10] Documentation
    Vivek Goyal wrote:
    >> Hi Vivek,
    >>
    >> I would be interested in knowing if these are the results expected?
    >>
    >
    > Hi Dhaval,
    >
    > Good question. Keeping current expectation in mind, yes these are expected
    > results. To begin with, current expectations are that try to emulate
    > cfq behavior and the kind of service differentiation we get between
    > threads of different priority, same kind of service differentiation we
    > should get from different cgroups.
    >
    > Having said that, in theory a more accurate estimate should be amount
    > of actual disk time a queue/cgroup got. I have put a tracing message
    > to keep track of total service received by a queue. If you run "blktrace"
    > then you can see that. Ideally, total service received by two threads
    > over a period of time should be in same proportion as their cgroup
    > weights.
    >
    > It will not be easy to achive it given the constraints we have got in
    > terms of how to accurately we can account for disk time actually used by a
    > queue in certain situations. So to begin with I am targetting that
    > try to meet same kind of service differentation between cgroups as
    > cfq provides between threads and then slowly refine it to see how
    > close one can come to get accurate numbers in terms of "total_serivce"
    > received by each queue.

    Hi Vivek,

    I simply tested with blktrace opened. I create two groups and set ioprio
    4 and 7 respectively(the corresponding weight should 4:1, right?), and
    start two dd concurrently. UUIC, Ideally, the proportion of service two
    dd got should be 4:1 in a period of time when they are running. I extract
    *served* value from blktrace output and sum them up. I found the proportion
    of the sum of *served* value is about 1.7:1
    Am i missing something?

    I extract the following highlight value
    8,0 0 0 18.914906549 0 m N 6601ioq served=*0x13* total service=0x184d

    >
    > Thanks
    > Vivek
    >
    >
    >

    --
    Regards
    Gui Jianfeng



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