Gentoo Archives: gentoo-user

From: Meino Christian Cramer <Meino.Cramer@×××.de>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] SATA tuning ?
Date: Wed, 16 Aug 2006 05:28:56
Message-Id: 20060816.072425.41631212.Meino.Cramer@gmx.de
In Reply to: Re: [gentoo-user] SATA tuning ? by Richard Fish
1 From: "Richard Fish" <bigfish@××××××××××.org>
2 Subject: Re: [gentoo-user] SATA tuning ?
3 Date: Tue, 15 Aug 2006 21:47:20 -0700
4
5 > Moving this back to gentoo-user, as I accidentally replied off list.
6 >
7 > Meino, please don't CC me directly on replies. I'll read them on the list...
8
9 ...sorry...my fault...bu the previous mail was a private one to me...
10
11 > On 8/15/06, Meino Christian Cramer <Meino.Cramer@×××.de> wrote:
12 > > > > WHen doing things, which mixes higher CPU-loads with massive hd
13 > > > > utilization, things are going slow (compilation of Blender for
14 > > > > example).
15 > > >
16 > > > Ok, let's try to test that. We'll start by saturating your CPU(s).
17 > > > On one terminal start "bzip2 -9 < /dev/urandom >/dev/null".
18 > >
19 > > This commandline puts a BIG SMILE onto my face ! Yes, this is as
20 > > simple as it is genious!!! Great! Really a nice CPU barbeque !
21 > >
22 > > > (If you
23 > > > have multiple processors, start one of these bzip2 commands on one
24 > > > terminal for each processor you have).
25 > > >
26 > > > Then on another, repeat the "hdparm -Tt /dev/sda"
27 > >
28 > > These are the results __without__ the CPU roaster:
29 > >
30 > > solfire:Mail/vim>sudo hdparm -tT /dev/sda
31 > > /dev/sda:
32 > > Timing cached reads: 2996 MB in 2.00 seconds = 1499.13 MB/sec
33 > > Timing buffered disk reads: 174 MB in 3.01 seconds = 57.79 MB/sec
34 > >
35 > > and this are the results __with__ the CPU roaster:
36 > >
37 > > solfire:/home/mccramer>sudo hdparm -Tt /dev/sda
38 > > solfire:/home/mccramer>sudo hdparm -Tt /dev/sda
39 > > /dev/sda:
40 > > Timing cached reads: 2160 MB in 2.10 seconds = 1030.12 MB/sec
41 > > Timing buffered disk reads: 174 MB in 3.03 seconds = 57.41 MB/sec
42 > >
43 > >
44 > > The chached reads dropped by ~469MByte/s. The buffered reads are
45 > > nearly the same.
46 >
47 > The buffered reads are all we care about. They are the actual reads
48 > from the disk to RAM. The cached reads is just a repeated read of the
49 > same sector of the disk, so today is really just a test of your memory
50 > bandwidth. Since we are loading memory and the CPU pretty heavily for
51 > this test, and significant drop is to be expected.
52
53 Ok...sounds good -- in the sense of: It seems, that I have no
54 hardware problem anywhere in my Linux box...
55
56 > So, it is not CPU utilization that is hurting your performance.
57
58 ( :) imaging the above sentence *WITHOUT* the current context :) )
59
60 This is the eigth wonder of the world...the first time when CPU load
61 does *not* hurt system performance! Oh yeah! I will send all my
62 render tasks to the...floppy controller, hahahahahahaa :))))))
63
64 (sorry could not resist...I am a little daft this morning as it seems :O))
65
66 > You mentioned problems compiling. The most likely case I can think of
67 > is that you do not have enough memory, and are inducing the system to
68 > swap.
69
70 Hmmm...1GByte Dualchannel-RAM should be enough for compiling Blender
71 (for example).
72
73 > Indeed when compiling most programs, you should see very little
74 > if any disk activity.
75
76 My SATA disk (Seagate ST3200827AS) is heavily shakeing its head when
77 compiling...
78
79 > This is particularly suspect if you have
80 > something like MAKEOPTS=-j4.
81
82 Yes, normally I use "make -j 4" for useing both cores.
83
84 May be I foolishly forget something to switch on or off in my BIOS
85 while migrating from PATA to SATA ? The only PATAs in my system is a
86 Plextor CD reader/burner and a LG DVD reader/burner on IDE1
87 (scnd. channel).
88
89 My mobo is a ASUS AV8 with AMI BIOS (upgraded to the "newest"
90 version I could find on the net).
91
92 > Regards,
93 > -Richard
94 > --
95 > gentoo-user@g.o mailing list
96 >
97 --
98 gentoo-user@g.o mailing list

Replies

Subject Author
Re: [gentoo-user] SATA tuning ? Andrew Frink <andrew.frink@×××××.com>