1 |
On Sun, 2008-01-27 at 10:58 +0100, Justin wrote: |
2 |
> Hey guys! |
3 |
> |
4 |
> Yesterday I found this article |
5 |
> http://gentoo-wiki.com/HOWTO_Speed_up_decompression_with_pbzip2 and |
6 |
> was very happy, because I'm an owner of an Q6600. |
7 |
> |
8 |
> So I tried to reproduce the benchmark from the wiki article but got |
9 |
> that bad results: |
10 |
> |
11 |
> test # time bzip2 -d -kf linux-2.6.23.tar.bz2 |
12 |
> |
13 |
> real 0m11.672s |
14 |
> user 0m11.306s |
15 |
> sys 0m0.367s |
16 |
> |
17 |
> |
18 |
> test # time pbzip2 -d -p4 -kf linux-2.6.23.tar.bz2 |
19 |
> |
20 |
> real 0m25.554s |
21 |
> user 0m24.862s |
22 |
> sys 0m0.683s |
23 |
> |
24 |
> So the parallel version took more than the double time! |
25 |
> |
26 |
> To test whether this is a problem of my Pc I tested this on an Dual |
27 |
> Core with the same result. |
28 |
> |
29 |
> An test with 7z was much better: |
30 |
> |
31 |
> |
32 |
> test # time 7za x -y linux-2.6.23.tar.bz2 |
33 |
> |
34 |
> real 0m4.642s |
35 |
> user 0m8.379s |
36 |
> sys 0m0.327s |
37 |
> |
38 |
|
39 |
> So my questions is what did I do wrong? |
40 |
|
41 |
|
42 |
Did you compress it with pbzip2 in the first place? |
43 |
|
44 |
Pbzip2 can only speed up decompression of files created by pbzip2, as |
45 |
well. Read the docs, dude ... |
46 |
|
47 |
p7zip has got its own implementation of bzip2, which might be faster. |