Thread: My 4K Write Program is nowhere near as fast as benchmarks

So I wrote this program that writes 100,000 4K .txt files onto disk.

HD Tune Pro says my 500 MB RAM disk gets ~90k IOPS for 4k files, ~350 MB/sec

Here is my program:

Code:

#include <iostream>
#include <fstream>
#include <cstdio>

int main() {
    char filename[100];

    for(double o = 1; o<100000; o++)
    {
        std::sprintf(filename, "%05.0lf.txt", o);
        std::ofstream ofs(filename);

        for(int i = 0; i < 77; i++)
        {
            ofs << "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
        }

        ofs << "aaaaaaaaaaaaaaa";
    }

    return 0;
}

Which gives me ~400 IOPS on the ramdisk. How can I make this go faster?

Thanks!

Apart from what memcpy says, you cant test it that way because creating so many files means lots of reads and writes to and from the directory. As such, I would expect a program such as the above to take more than twice as long as quoted.
All you're doing is wearing out the disk faster.
What would make sense for testing write speed would be to append 4096 bytes to a binary file at a time. You would only have the one file.
You would use the "write" member function.