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D - wc in D

reply joe vpop.net writes:
Hi,

I just heard about D, and thought I'd give it a try.
I ran the wc D program found here:
http://www.digitalmars.com/d/wc.html
on a 196MB file on linux.

I got the numbers output to me in about 3 seconds,
however I had to wait 6 more *minutes* before the
program ended.  The resident size of the program
was about 188MB.

This contrasts with /usr/bin/wc which ran in about
3 seconds and used 300KB of memory.

Anyways, it looks like D is trying to do garbage collection
at the end of the program when it doesn't need to... it
can just exit.  Also, the 6 minutes seems a bit long.

thanks,
-joe
Feb 26 2004
parent Sean Kelly <sean ffwd.cx> writes:
joe vpop.net wrote:
 Hi,
 
 I just heard about D, and thought I'd give it a try.
 I ran the wc D program found here:
 http://www.digitalmars.com/d/wc.html
 on a 196MB file on linux.
 
 I got the numbers output to me in about 3 seconds,
 however I had to wait 6 more *minutes* before the
 program ended.  The resident size of the program
 was about 188MB.

I think the wc example was a bit simplified because it was an example. std.file.read will read the entire file into a memory buffer. This isn't most efficient approach with a 196MB file. This would also explain why the memory footprint of the program was almost the same as the file size. A more efficient approach would be to use std.stream. You could try to adapt the program as an exercise :)
 Anyways, it looks like D is trying to do garbage collection
 at the end of the program when it doesn't need to... it
 can just exit.  Also, the 6 minutes seems a bit long.

Agreed. Sean
Feb 26 2004