nvme-feat-perfc(1)
==================

NAME
----
nvme-feat-perfc - Get and set performance characteristics feature

SYNOPSIS
--------
[verse]
'nvme' [<global-options>] 'feat perfc' <device>
			[--namespace-id=<nsid> | -n <nsid>] [--attri=<attri> | -a <attri>]
			[--rvspa | -r] [--r4karl=<r4karl> | -R <r4karl>]
			[--paid=<paid> | -p <paid>] [--attrl=<attrl> | -A <attrl>]
			[--vs-data=<file> | -V <file>]
			[--sel=<select> | -S <select>] [--save | -s]

DESCRIPTION
-----------
Get and set performance characteristics feature.

The <device> parameter is mandatory and may be either the NVMe character
device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1).

If any of the setting options (`--rvspa`, `--r4karl`, or `--paid`) are specified,
the command will update the performance characteristics configuration. If none
of these options are specified, it will retrieve and display the current
configuration.

On success it returns 0, error code otherwise.

OPTIONS
-------
-n <nsid>::
--namespace-id=<nsid>::
	Optional namespace attached to controller.

-a <attri>::
--attri=<attri>::
	Attribute index. Specifies the performance attribute index to set or get.

-r::
--rvspa::
	Revert vendor specific performance attribute flag.

-R <r4karl>::
--r4karl=<r4karl>::
	Random 4 KiB average read latency.

-p <paid>::
--paid=<paid>::
	Performance attribute identifier. Must be a valid UUID string format.

-A <attrl>::
--attrl=<attrl>::
	Attribute length. Required when using vendor specific performance data.

-V <file>::
--vs-data=<file>::
	Vendor specific data input file path. Reads data buffer from the specified file.

-S <select>::
--sel=<select>::
	Select (SEL): This field specifies which value of the attributes
	to return in the provided data:

-s::
--save::
	Save the attribute so that it persists through all power states and resets.

include::global-options.txt[]

EXAMPLES
--------
* Has the program issue a feat perfc to get the current configuration:
+
------------
# nvme feat perfc /dev/nvme0
------------

* Has the program issue a feat perfc to set standard performance attributes:
+
------------
# nvme feat perfc /dev/nvme0 --attri=0 --r4karl=10 --save
------------

* Has the program issue a feat perfc to set vendor specific data from a file:
+
------------
# nvme feat perfc /dev/nvme0 --attri=128 --paid=12345678-1234-1234-1234-123456789abc --attrl=64 --vs-data=vs_buf.bin
------------

NVME
----
Part of the nvme-user suite.
