Gentoo Archives: gentoo-user

From: Simon <turner25@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Tips for saving power needed...
Date: Mon, 02 Apr 2012 14:19:52
Message-Id: CAN1q39VQQnaAAmFW6=d60ggof+t1+1-tWSirwz+EDJGd_4+5hQ@mail.gmail.com
In Reply to: Re: [gentoo-user] Tips for saving power needed... by Michael Mol
1 There's "powertop" that I use, which shows a listing of things that are
2 keeping the computer busy. And it gives recommendations on how to lower
3 power usage (including setting kernel options, enabling/disabling stuff in
4 /sys, etc...). It also estimates power consumption in Watts and gives you
5 approx time left.
6
7 Many recomendations already posted in this emails will be suggested by
8 powertop.
9
10 Simon
11
12 On Mon, Apr 2, 2012 at 8:10 AM, Michael Mol <mikemol@×××××.com> wrote:
13
14 > On Mon, Apr 2, 2012 at 7:57 AM, Pandu Poluan <pandu@××××××.info> wrote:
15 > >
16 > > On Apr 2, 2012 5:00 PM, "Robert David" <robert.david.public@×××××.com>
17 > > wrote:
18 > >>
19 > >> Hi,
20 > >>
21 > >> maybe write your hw configuration first. Eg: CPUs, graphic cards, HDDs
22 > >> (size, speed, type) and others.
23 > >>
24 > >> Also provide lspci output and /proc/cpuinfo.
25 > >>
26 > >> Then this is a server, maybe with more than one GB nic. If you dont use
27 > >> spare nics disable them in bios. Do the same with other unneeded stuff.
28 > >>
29 > >> If you can access your server and replace cards, remove everything you
30 > >> dont need. Do not lower fans or dont play with cpu voltage. If you want
31 > >> to run this server 24/7 it can cause serious problems. It will not save
32 > >> you much power. Paradoxly this could lead to higher power usage in
33 > >> some cases, because of hotter devices.
34 > >>
35 > >> Remove spare memory cards, if you dont need much memory, etc.
36 > >>
37 > >> Robert.
38 > >>
39 > >> V Sun, 01 Apr 2012 17:04:58 +0200
40 > >> Jarry <mr.jarry@×××××.com> napsáno:
41 > >>
42 > >> > Hi,
43 > >> >
44 > >> > admin of a colo-center keeps complaining my server is going
45 > >> > a little over power-limit (which they have set as ~120W per
46 > >> > 24h/avg, while my server needs ~130-135W). So I need to find
47 > >> > a way to save at least those 15W, or I will be moved to
48 > >> > higher tarif (which means higher costs for server-housing).
49 > >> >
50 > >> > Before going hard(ware) way, I would like to try first
51 > >> > all possible software solutions. What I tried up to now is
52 > >> > cpufreqd, CONFIG_NO_HZ=y, and spindown. In addition to that
53 > >> > I adjusted fan-speeds to a little lower values and turned
54 > >> > off some unneeded peripherials (in bios).
55 > >> >
56 > >> > Is there anything else I could do? Any tips would be greatly
57 > >> > welcomed...
58 > >> >
59 > >> > Jarry
60 > >> >
61 > >>
62 > >>
63 > >
64 > > I'd rather have *more* RAM than causing unnecessary swaps.
65 > >
66 > > Try using a smaller swapfile to reduce swap tendencies. You can always
67 > push
68 > > a larger swapfile into service when needed.
69 > >
70 > > There's also a kernel knob to set 'swappiness', but I forget what
71 > exactly.
72 > > Try 'sysctl -a | grep swap'
73 >
74 > Swappiness is the knob you want to set if you want to reduce
75 > swappiness. I set mine to 0; swap only when absolutely necessary.
76 >
77 > In /etc/sysctl.conf:
78 > vm.swappiness = 0
79 >
80 > On the command line:
81 > sysctl -w vm.swappiness=0
82 >
83 > --
84 > :wq
85 >
86 >