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    SubjectRe: gettimeofday problem
    On Mon, Jun 24, 2002 at 12:20:02PM +0200, Salvatore D'Angelo wrote:
    > In this piece of code I convert seconds and microseconds in
    > milliseconds. I think the problem is not in my code, in fact I wrote the
    > following piece of code in Java, and it does not work too. In the for
    > loop the 90% of times b > a while for 10% of times not.
    > long a = System.currentTimeMillis();
    > long b = System.currentTimeMillis();
    > if (a > b) {
    > System.out.println("Wrong!!!!!!!!!!!!!");
    > }

    So in 10% of the cases, two successive calls yield time
    rolling BACK ?

    I used gettimeofday() call, and compared the original data
    from the code.

    At a modern uniprocessor machine I never get anything except
    monotonously increasing time (TSC is used in betwen timer ticks
    to supply time increase.) At a dual processor machine, on
    occasion I do get SAME value twice. I have never seen time
    rolling backwards.

    Uh.. correction: 216199245 0:-1 -- it did step backwards,
    but only once within about 216 million gettimeofday() calls.
    (I am running 2.4.19-pre8smp at the test box.)

    /Matti Aarnio
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