Documentation: update tunable options in block/cfq-iosched.txt
Update tunable options in block/cfq-iosched.txt. Signed-off-by: Namjae Jeon <linkinjeon@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>hifive-unleashed-5.1
parent
2792d87193
commit
4004e90cfa
|
@ -9,20 +9,71 @@ These files are the ones found in the /sys/block/xxx/queue/ directory.
|
||||||
Files denoted with a RO postfix are readonly and the RW postfix means
|
Files denoted with a RO postfix are readonly and the RW postfix means
|
||||||
read-write.
|
read-write.
|
||||||
|
|
||||||
|
add_random (RW)
|
||||||
|
----------------
|
||||||
|
This file allows to trun off the disk entropy contribution. Default
|
||||||
|
value of this file is '1'(on).
|
||||||
|
|
||||||
|
discard_granularity (RO)
|
||||||
|
-----------------------
|
||||||
|
This shows the size of internal allocation of the device in bytes, if
|
||||||
|
reported by the device. A value of '0' means device does not support
|
||||||
|
the discard functionality.
|
||||||
|
|
||||||
|
discard_max_bytes (RO)
|
||||||
|
----------------------
|
||||||
|
Devices that support discard functionality may have internal limits on
|
||||||
|
the number of bytes that can be trimmed or unmapped in a single operation.
|
||||||
|
The discard_max_bytes parameter is set by the device driver to the maximum
|
||||||
|
number of bytes that can be discarded in a single operation. Discard
|
||||||
|
requests issued to the device must not exceed this limit. A discard_max_bytes
|
||||||
|
value of 0 means that the device does not support discard functionality.
|
||||||
|
|
||||||
|
discard_zeroes_data (RO)
|
||||||
|
------------------------
|
||||||
|
When read, this file will show if the discarded block are zeroed by the
|
||||||
|
device or not. If its value is '1' the blocks are zeroed otherwise not.
|
||||||
|
|
||||||
hw_sector_size (RO)
|
hw_sector_size (RO)
|
||||||
-------------------
|
-------------------
|
||||||
This is the hardware sector size of the device, in bytes.
|
This is the hardware sector size of the device, in bytes.
|
||||||
|
|
||||||
|
iostats (RW)
|
||||||
|
-------------
|
||||||
|
This file is used to control (on/off) the iostats accounting of the
|
||||||
|
disk.
|
||||||
|
|
||||||
|
logical_block_size (RO)
|
||||||
|
-----------------------
|
||||||
|
This is the logcal block size of the device, in bytes.
|
||||||
|
|
||||||
max_hw_sectors_kb (RO)
|
max_hw_sectors_kb (RO)
|
||||||
----------------------
|
----------------------
|
||||||
This is the maximum number of kilobytes supported in a single data transfer.
|
This is the maximum number of kilobytes supported in a single data transfer.
|
||||||
|
|
||||||
|
max_integrity_segments (RO)
|
||||||
|
---------------------------
|
||||||
|
When read, this file shows the max limit of integrity segments as
|
||||||
|
set by block layer which a hardware controller can handle.
|
||||||
|
|
||||||
max_sectors_kb (RW)
|
max_sectors_kb (RW)
|
||||||
-------------------
|
-------------------
|
||||||
This is the maximum number of kilobytes that the block layer will allow
|
This is the maximum number of kilobytes that the block layer will allow
|
||||||
for a filesystem request. Must be smaller than or equal to the maximum
|
for a filesystem request. Must be smaller than or equal to the maximum
|
||||||
size allowed by the hardware.
|
size allowed by the hardware.
|
||||||
|
|
||||||
|
max_segments (RO)
|
||||||
|
-----------------
|
||||||
|
Maximum number of segments of the device.
|
||||||
|
|
||||||
|
max_segment_size (RO)
|
||||||
|
---------------------
|
||||||
|
Maximum segment size of the device.
|
||||||
|
|
||||||
|
minimum_io_size (RO)
|
||||||
|
--------------------
|
||||||
|
This is the smallest preferred io size reported by the device.
|
||||||
|
|
||||||
nomerges (RW)
|
nomerges (RW)
|
||||||
-------------
|
-------------
|
||||||
This enables the user to disable the lookup logic involved with IO
|
This enables the user to disable the lookup logic involved with IO
|
||||||
|
@ -45,11 +96,24 @@ per-block-cgroup request pool. IOW, if there are N block cgroups,
|
||||||
each request queue may have upto N request pools, each independently
|
each request queue may have upto N request pools, each independently
|
||||||
regulated by nr_requests.
|
regulated by nr_requests.
|
||||||
|
|
||||||
|
optimal_io_size (RO)
|
||||||
|
--------------------
|
||||||
|
This is the optimal io size reported by the device.
|
||||||
|
|
||||||
|
physical_block_size (RO)
|
||||||
|
------------------------
|
||||||
|
This is the physical block size of device, in bytes.
|
||||||
|
|
||||||
read_ahead_kb (RW)
|
read_ahead_kb (RW)
|
||||||
------------------
|
------------------
|
||||||
Maximum number of kilobytes to read-ahead for filesystems on this block
|
Maximum number of kilobytes to read-ahead for filesystems on this block
|
||||||
device.
|
device.
|
||||||
|
|
||||||
|
rotational (RW)
|
||||||
|
---------------
|
||||||
|
This file is used to stat if the device is of rotational type or
|
||||||
|
non-rotational type.
|
||||||
|
|
||||||
rq_affinity (RW)
|
rq_affinity (RW)
|
||||||
----------------
|
----------------
|
||||||
If this option is '1', the block layer will migrate request completions to the
|
If this option is '1', the block layer will migrate request completions to the
|
||||||
|
|
Loading…
Reference in New Issue