Re: microtime questions

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Tedd,

The only way that I can even think of this as being possible is if you call
microtime() instead of microtime(true). The former will return 'msec sec'
separated by a space which can produce a negative number because you've
essentially got two different types of measurements there. IMHO PHP should
probably throw out an error when two strings are used in a mathematical way
- in this case (without the TRUE arg) here is a possible equation that could
be evaluated.

  0.15290800 1144430717
- 0.86641600 1144430716

PHP evaluates this to -0.713508 (or 0.15290800 - 0.86641600) It's negative
because we're not talking about msecs from the same second - it ignores the
seconds and only pays attention to the microseconds. So if you're using
microtime(true) how can this happen on your machine? Well, off the top of my
head I think you should verify that your machine (or your hosting service)
is running PHP5 || >. IF not, and error reporting is turned off, then you'll
get a negative number from time to time since the seconds are being ignored.

http://php.net/microtime has an example of how to emulate microtime(true) on
PHP < 5

Hope that helps!
-Joe

On 4/7/06, Brad Bonkoski <bbonkoski@xxxxxxxxxxxxxx> wrote:
>
> How is the CPU not in question?  Does this script run on air?
> It may not be YOUR CPU, but it is still a CPU bound by the sceduling
> algorithm of the Operating System, so the time differentials are too be
> expected.
> -B
>
> tedd wrote:
>
> > At 12:24 PM -0400 4/7/06, Brad Bonkoski wrote:
> >
> >> Interesting...
> >> as for your first question...
> >> Know that PHP/Apache does not have free reign to your CPU, so the
> >> times could be different based on the scheduling going on in the OS
> >> kernel.
> >>
> >> As for the second one...
> >> No idea why you would get a negative number, I just copied and ran
> >> from the command line and did not encounter 1 negative time for about
> >> 30 runs....
> >>
> >> Do you get negative times if you run it from the command line as well?
> >> -B
> >>
> >>> RE:
> >>>
> >>> http://www.xn--ovg.com/microtime.php
> >>>
> >
> > Brad:
> >
> > Thanks for looking.
> >
> > My questions are with regard to what happens on the site, not via my
> > command line. As such, my command line and my CPU are not involved.
> >
> > Can you answer the questions as they pertain to the site in question?
> >
> > Thanks.
> >
> > tedd
> >
>
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