projects / thirdparty / util-linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 22853e4a KZ |
1 | .\" -*- nroff -*- |
| 2 | .TH ELVTUNE 8 "14 March 2000" "Version 1.0" | |
| 3 | .SH NAME | |
| 4 | elvtune \- I/O elevator tuner | |
| 5 | .SH SYNOPSIS | |
| 6 | .B elvtune | |
| 7 | [ | |
| 8 | .B \-r | |
| 9 | .I r_lat | |
| 10 | ] | |
| 11 | [ | |
| 12 | .B \-w | |
| 13 | .I w_lat | |
| 14 | ] | |
| 15 | [ | |
| 16 | .B \-b | |
| 17 | .I b_max | |
| 18 | ] | |
| 19 | .B /dev/blkdev1 | |
| 20 | [ | |
| 21 | .B /dev/blkdev2 ... | |
| 22 | ] | |
| 23 | ||
| 24 | .B elvtune | |
| 25 | .B -h | |
| 26 | ||
| 27 | .B elvtune | |
| 28 | .B -v | |
| 29 | .SH DESCRIPTION | |
| 30 | .B elvtune | |
| 31 | allows to tune the I/O elevator per blockdevice queue basis. The | |
| 32 | tuning can be safely done at runtime. Tuning the elevator means | |
| 33 | being able to change disk performance and interactiveness. In the | |
| 34 | output of elvtune the address of the queue tuned will be shown | |
| 35 | and it can be considered as a queue ID. | |
| 36 | For example multiple partitions in the same harddisk will | |
| 37 | share the same queue and so tuning one partition will be | |
| 38 | like tuning the whole HD. | |
| 39 | .SH OPTIONS | |
| 40 | .TP | |
| 41 | .BI -r \ r_lat | |
| 42 | set the max latency that the I/O scheduler will provide on | |
| 43 | each read. | |
| 44 | .TP | |
| 45 | .BI -w \ w_lat | |
| 46 | set the max latency that the I/O scheduler will provide on | |
| 47 | each write. | |
| 48 | .TP | |
| 49 | .BI -b \ b_max | |
| 50 | max coalescing factor allowed on writes when there are reads | |
| 51 | pending in the queue. | |
| 52 | .TP | |
| 53 | .BI -h | |
| 54 | help. | |
| 55 | .TP | |
| 56 | .BI -v | |
| 57 | version. | |
| 58 | .SH NOTE | |
| 59 | Actually the only fields tunable are those relative | |
| 60 | to the IO scheduler. It's not possible to select | |
| 61 | a one-way or two-way elevator yet. | |
| 62 | .PP | |
| 63 | For logical blockdevices like LVM the tuning has to | |
| 64 | be done on the | |
| 65 | .I physical | |
| 66 | devices. Tuning the queue of the LVM logical device | |
| 67 | is useless. | |
| 68 | .SH RETURN VALUE | |
| 69 | 0 on success and 1 on failure. | |
| 70 | .SH HISTORY | |
| 71 | Ioctls for tuning elevator behaviour were added in Linux 2.3.99-pre1. | |
| 72 | .SH AUTHORS | |
| 73 | Andrea Arcangeli <andrea@suse.de> SuSE | |
| 86d62711 KZ |
74 | .SH AVAILABILITY |
| 75 | The elvtune command is part of the util-linux-ng package and is available from | |
| 76 | ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/. |