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2015.01.01 17:12 "Re: [Tiff] Fast TIFF Reading on Windows", by Bob Friesenhahn
- 2015.01.01 17:27 "Re: [Tiff] Fast TIFF Reading on Windows", by John
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2015.01.01 20:20 "Re: [Tiff] Fast TIFF Reading on Windows", by Aaron Boxer
- 2015.01.03 05:24 "Re: [Tiff] Fast TIFF Reading on Windows", by Edward Lam
- 2015.01.05 13:47 "[Tiff] Fwd: Fast TIFF Reading on Windows", by Aaron Boxer
2015.01.05 03:39 "Re: [Tiff] Fast TIFF Reading on Windows", by Aaron Boxer
Another finding: reading files with four threads (I have a quad core i7) is about twice as fast as single threaded reads.
On Sun, Jan 4, 2015 at 10:36 PM, Aaron Boxer <boxerab@gmail.com> wrote:
Gentlemen,
My very informal benchmark (windows 7, SSD, RamMAP tool to clear OS file cache before each run):
- twiddling windows flags made no difference to speed
- TIFFOpenfile with mode "ru" i.e. disabling memory mapping, was 3 times
slower than with default flag "r"
So, my conclusion is that memory mapping is the way to go for performance.
On Sat, Jan 3, 2015 at 12:24 AM, Edward Lam <edward@sidefx.com> wrote:
On Thu, January 1, 2015 15:20, Aaron Boxer wrote:
Thanks. Yes, my use case is: first-read of many 10-15 MB RGB
>> uncompressed
files. Unfortunately, I don't have control over how the files are stored, i.e. block size. One nice feature on Linux is fadvise, where I can specify FADV_SEQUENTIAL | FADV_DONTNEED, which would be right for my use case.
On Windows, the CreateFile() API has additional flags that you may wish to explore like FILE_FLAG_SEQUENTIAL_SCAN and/or FILE_FLAG_NO_BUFFERING
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363858%28v=vs.85%29.aspx#caching_behavior