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From:Michael Widenius Date:January 10 2000 10:55pm
Subject:Irrelevant ...mmap() VS read()
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>>>>> "Mark" == Mark Papadakis <markp@stripped> writes:

Mark> Hi!
Mark> I am sorry if its kinda irrelevant but I wanted an opinion in this before
> actually doing it.

Mark> About 80.000 reads are perfomed in my application in about 20cs.

Mark> Would it be faster to dump open()/read() and use mmap() and access the abstract
> memory layer instead?
Mark> And if so, how much faster would it be?

Mark> One element at a time is being read ( i.e 1 integer ).

Mark> Thank you,

Hi!

On many OS reads are made by doing a mmap()+ a copy from memory + an
un-mmap().  (On Solaris someone claimed that each reads make 3 mmap() calls).

This means that using mmap directly will be faster, possible 0-20 %
faster...

Regards,
Monty
Thread
Irrelevant ...mmap() VS read()Mark Papadakis9 Jan
  • Re: Irrelevant ...mmap() VS read()Sasha Pachev10 Jan
    • Re: Irrelevant ...mmap() VS read()elble10 Jan
      • Re: Irrelevant ...mmap() VS read()Michael Widenius26 Jan
        • Re: Irrelevant ...mmap() VS read()Mathijs Brands27 Jan
          • Re: Irrelevant ...mmap() VS read()Michael Widenius28 Jan
            • Re: Irrelevant ...mmap() VS read()Mathijs Brands29 Jan
              • Re: Irrelevant ...mmap() VS read()Michael Widenius29 Jan
    • Re: Irrelevant ...mmap() VS read()Mike Wexler10 Jan
  • Irrelevant ...mmap() VS read()Michael Widenius11 Jan