Re: performance issues

From: Joaquin Cuenca Abela (e98cuenc@yahoo.com)
Date: Tue Jul 23 2002 - 07:17:14 EDT

  • Next message: Tomas Frydrych: "commit: optimize justified text run handling"

    --- Tomas Frydrych <tomas@frydrych.uklinux.net> wrote:
    >
    > Hi Joaquin,
    >
    > > Indeed, this 100 times factor is quite important,
    > because we end
    > > calling some fp_Run methods (for each run in each
    > line). We have
    > > ~25.6 runs by line, so that means that we call
    > 2560 times some fp_Run
    > > methods.
    >
    > I guess your document has the text in it justified?

    No, AFAIR the text was right ragged (only left
    aligned).

    > In non-justified text
    > we only have 1 run per line if the formatting is
    > consisten across the
    > line;

    I was seeing 1 run per word + 1 run per space, so ~2
    runs per word on left aligned text (I will double
    check it when I will be back at home).

    > in justified text we have two runs per word. I
    > think it should be
    > straight forward to improve the hanling of justified
    > text so that in the
    > TextRun we would keep a vector of pair of numbers
    > {offset,length}
    > which would indicate where in the run chunks of
    > spaces start and
    > how long they are, and we could draw then our run in
    > segments,
    > advancing the drawing point over the spaces. This
    > would save us lot
    > of memory and processing time for justified text,
    > costing only 4 extra
    > bytes per textrun in non-justified paragraph.

    Something like that may help, but take in account that
    our problems comes (AFAICS) from a x1000 times factor
    on the number of runs (the x100 times factor is what I
    explained in my last email, the 10 times remaining
    seems to be due to just little stupid errors).

    If you're able to reduce the runs to ~1 run by line I
    will rerun the tests and see how it affects speed.

    Cheers,

    =====
    Joaquin Cuenca Abela
    e98cuenc@yahoo.com

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