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Annotated edit history of elvtune(8) version 1, including all changes. View license author blame.
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1 perry 1 ELVTUNE
2 !!!ELVTUNE
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 NOTE
8 RETURN VALUE
9 HISTORY
10 AUTHORS
11 ----
12 !!NAME
13
14
15 elvtune - I/O elevator tuner
16 !!SYNOPSIS
17
18
19 __elvtune__ [[ __-r__ ''r_lat'' ] [[ __-w__
20 ''w_lat'' ] [[ __-b__ ''b_max'' ]
21 __/dev/blkdev1__ [[ __/dev/blkdev2 ...__ ]
22
23
24 __elvtune -h__
25
26
27 __elvtune -v__
28 !!DESCRIPTION
29
30
31 __elvtune__ allows to tune the I/O elevator per
32 blockdevice queue basis. The tuning can be safely done at
33 runtime. Tuning the elevator means being able to change disk
34 performance and interactiveness. In the output of elvtune
35 the address of the queue tuned will be shown and it can be
36 considered as a queue ID. For example multiple partitions in
37 the same harddisk will share the same queue and so tuning
38 one partition will be like tuning the whole HD.
39 !!OPTIONS
40
41
42 __-r__ ''r_lat''
43
44
45 set the max latency that the I/O scheduler will provide on
46 each read.
47
48
49 __-w__ ''w_lat''
50
51
52 set the max latency that the I/O scheduler will provide on
53 each write.
54
55
56 __-b__ ''b_max''
57
58
59 max coalescing factor allowed on writes when there are reads
60 pending in the queue.
61
62
63 __-h__
64
65
66 help.
67
68
69 __-v__
70
71
72 version.
73 !!NOTE
74
75
76 Actually the only fields tunable are those relative to the
77 IO scheduler. It's not possible to select a one-way or
78 two-way elevator yet.
79
80
81 For logical blockdevices like LVM the tuning has to be done
82 on the ''physical'' devices. Tuning the queue of the LVM
83 logical device is useless.
84 !!RETURN VALUE
85
86
87 0 on success and 1 on failure.
88 !!HISTORY
89
90
91 Ioctls for tuning elevator behaviour were added in Linux
92 2.3.99-pre1.
93 !!AUTHORS
94
95
96 Andrea Arcangeli
97 ----
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