1 |
Hello list |
2 |
|
3 |
Long time no read... :) |
4 |
|
5 |
It follows a verbose preamble. For the actual questions see dashed line below. |
6 |
TL;DR summary: it’s all about ricer-performance questions on a netbook. |
7 |
|
8 |
|
9 |
I have the luck of having obtained a used netbook for free (Atom N450, single- |
10 |
core with HT, 1 GB memory, 5400 rev HDD). During the last week I’ve been |
11 |
experimenting with 32 and 64 bits on it and am still quite undecided which to |
12 |
keep. My reasons: |
13 |
|
14 |
- They are not as far apart in CPU performance as is the Core2. |
15 |
I posted a 32/64 comparison for Core2 a few months ago, which showed that |
16 |
Lilypond speedup on 64 bit was 50%. On the Atom, it actually took 5% longer. |
17 |
(Sadly, Blender doesn’t build on 32 bit right now). |
18 |
- Startup times for hogs like Firefox and KDE are quite equal between the two |
19 |
(that could be attributed in parts to the fact that the 64 bit partition |
20 |
sits on the disk’s first sectors, while 32 bit sits at the other end, I |
21 |
don’t know which end is faster). |
22 |
- pro 64: it is very easy to use distcc, as opposed to 32 bits (see below). |
23 |
- con 64: it uses about 50% more memory, 32 bit builds are a little faster. |
24 |
|
25 |
The RAM argument is the most convincing one right now, since more free RAM |
26 |
means more cache, which means a faster system in the long run. Currently, KDE |
27 |
after logon needs 150 MB on 32 bit, and 250 MB on 64 bit (without akonadi for |
28 |
now). But awesome WM rocks on a netbook anyway. |
29 |
|
30 |
|
31 |
----------[ Questions begin ]------------------------------------------------ |
32 |
|
33 |
So I’m interested in you opinion and own experience about the following |
34 |
arising questions: |
35 |
|
36 |
* From my observations, the benefit of 64 bit over 32 is much smaller for an |
37 |
Atom than it is for my Core2. Am I right to assume thus that the Atom |
38 |
architecture doesn’t have much to offer to 64 bit (such as extra registers)? |
39 |
I’m not talking about memory here, since it’s limited to 2 GB in any case. |
40 |
|
41 |
* The problem of distcc between different architectures: |
42 |
The netbook already had an older 32 bit Gentoo installed. And since I have |
43 |
a multilib host (march=core2), I though I could upgrade with distcc (using |
44 |
march=atom on the netbook). But at some point more and more stuff stopped |
45 |
working, eventually I got “invalid instruction” errors during emerge, hence |
46 |
I figured that was a dead end. |
47 |
|
48 |
So is it possible to mix architectures in this way at all with distcc? |
49 |
I also have crossdev for i686 installed, which even shares files with the |
50 |
system’s normal multilib gcc. I find that odd. |
51 |
I sped up the installation process for 32 bit by using a chroot on the big |
52 |
machine, which worked nicely. But it’s not a long-term solution, b/c it |
53 |
uses up too much disk space on the host. |
54 |
|
55 |
* I’m interested in the question of -O2 vs. -Os. |
56 |
Some sources say -Os is bad, b/c it breaks debugging and is mainly untested. |
57 |
I won’t do heavy developing on it anyway, and Atoms do have a puny cache. |
58 |
So I wonder whether -Os would improve execution time and RAM usage |
59 |
noticably. Diskspace itself is not an issue. |
60 |
|
61 |
* I’m also interested in comparing bin packages over self-compiled ones. |
62 |
E.g. I did compile icedtea, even if it’s just for TV browser. :) |
63 |
Can you name a Java benchmark to measure CPU performance? |
64 |
|
65 |
* The last thing I’m going to set up is filesystem encryption, at least for ~. |
66 |
I already know/think that AES would be the best choice due to limited CPU |
67 |
power, but what else is there to heed besides key size? |
68 |
|
69 |
* What other small benchmarks for CPU and memory can you recommend? So far I |
70 |
tested with nbench and sysbench. The results are so-and-so. Some computation |
71 |
stuff is much slower on 64 bit, some a bit faster. The applicability to |
72 |
every-day use is of course a wibbly-wobbly argument. |
73 |
I also tested the runtime of some application (packing and unpacking of |
74 |
archives, throughput with dd, mencoder). If there is interest, I can post |
75 |
the result of 21 runs on each platform, measured with GNU time. |
76 |
|
77 |
----------[ Questions end ]-------------------------------------------------- |
78 |
|
79 |
|
80 |
PS.: I’m aware that benchmarks are always a bit subjective and none is |
81 |
perfect. I also realise that most of the questions quite belong into the |
82 |
ricer corner. But Netbooks are ricer devices, b/c they need to perform at |
83 |
their limits all the time. :-D |
84 |
|
85 |
If you read until this point, thank you very much for your time. You get a |
86 |
unicorn as a reward: `^nn~ |
87 |
-- |
88 |
Gruß | Greetings | Qapla’ |
89 |
Please do not share anything from, with or about me with any Facebook service. |
90 |
|
91 |
“Time is money” said the waiter and put the date on the bill. |