read() performance - Linux.too?

[Bob W]

/*
The std.file.read() function in dmd causes a performance
issue after reading large files from 100MB upwards.
Reading the file seems to be no problem, but cleanup
afterwards takes forever.

I am therefore using std.mmfile which works fine in the
Windows version of D, but using read() would be more
convenient in several cases.

Now a few questions:

1) Does anyone know if the read() performance problem
occurs in the Linux version of D as well?

2) Is there any info available where the real problem
sits? Allocating a few 100MB does not show the same
phenomenon and dmc's fread() function is also painless.

3) I did not find anything about this issue in Bugzilla.
Did I overlook the respective entry?

*/


// Try reading a 100MB+ file with the following
// program (some patience required):

import std.stdio, std.file;

alias writefln wrl;

void main(char[][] av) {
  wrl();
  if (av.length<2)  {
    wrl("Need file name to test read() !");
    return;
  }
  char[] fn=av[1];
  wrl("Reading '%s' ...", fn);
  char[] bf=cast(char[])read(fn);
  wrl("%d bytes read.",bf.length);
  wrl("Doing something ...");
  int n=0;
  foreach(c;bf)  n+=c;
  wrl("Result: %s, done.",n);
  wrl("Expect a delay here after reading a huge file ...");
  wrl();
}