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    SubjectRe: [PATCH] process cputimer is moving faster than its corresponding clock
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    On Wed, 2013-04-10 at 11:48 -0400, Olivier Langlois wrote:
    >
    > You have valid concerns and I will attempt to clarify the changes I
    > propose. Before I do, realise that as a first time patcher, I
    > sincerely
    > attempted to minimize the changes required to fix the posix cputimers.

    Right, I suspect some of that is what made me go yuck! when reading the
    patch. I feel some interfaces could be avoided if we refactor a bit
    more -- and given the complexity of the code its well worth doing.

    > The real source of the problem is that the process clock is distinct
    > from its cputimer. It is not explained why it is done like that in the
    > code but I understand that the benefit is that you can fetch the
    > cputimer value and avoiding the cost to traverse the list of tasks
    > member of the group. The price to pay however it is that it is painful
    > to make sure that the clock and its corresponding cputimer remain in
    > sync as they advance. With that in mind, I did all I can to minimize
    > thread group task list traversal when possible and do it only when
    > mandatory which is when you set a timer expiration time.

    Right, I hope my earlier email explained why it is so expensive and
    thus why they're separated.

    I'll try and dig through the rest of your email later.. sorry for being
    a tad slow etc.



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