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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 <email@example.com> wrote:
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 <firstname.lastname@example.org> 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
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