Writing data to disk in parallel?
c++-cli, image-processing, multithreading
Solution
Writing/reading in parallel to/from a single mechanical disk is not a good idea because the mechanical head needs to spin every time to service an I/O request, so using multiple threads will just bounce it around needlessly and create overhead.
You can try to benchmark a bit, but I'm afraid you'll just have to resort to using a single thread and writing sequentially.
Problem
So I am working on a C++/cli image processing library and am trying to optimize my code. Basically, I am passed a System::Drawing::Bitmap of the image, which I then need to write to disk, perform complex analysis on, and return the results of the analysis. I thought that I could write the image to disk in parallel to speed up things (my algorithm does not modify the image). However, I have not worked with threads much, so I wanted to get your input on what the best way to do this would be. ``` string ProcessImage(System::Drawing::Bitmap ^bmp, System::String^ targetFile) { bmp->Save(targetFile); System::Drawing::Bitmap^ bmp8 = BitmapConvertPixelFormat(bmp, 8); //<-- a function I wrote which converts the 32bpp I am passed into an 8bpp one string results = Analyze(bmp8); //<--- takes a good bit of time return results; } ``` Please let me know your thoughts. Thank you in advance!