NVME-FEAT-PERFC(1)

✨ NAME ✨ — nvme-feat-perfc

okay so bestie, this is nvme-feat-perfc from the NVMe Manual, and it’s literally the get-and-set performance characteristics feature. 💅✨

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🦋 SYNOPSIS 🦋

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]

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🌸 DESCRIPTION 🌸

This command gets and sets the performance characteristics feature. Iconic behavior, honestly. 🫶

The <device> parameter is mandatory, no skipping it. It can be either the NVMe character device — like /dev/nvme0 — or a namespace block device — like /dev/nvme0n1. Both examples are exactly that. ✨

If any of the setting options — --rvspa, --r4karl, or --paid — are specified, the command updates the performance characteristics configuration. If none of those options are specified, it retrieves and displays the current configuration instead. Lowkey a whole dual-purpose moment. 💖

On success it returns 0; otherwise you get an error code. Periodt.

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💅 OPTIONS 💅

• -n <nsid>, --namespace-id=<nsid> — optional namespace attached to the 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 the 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:
  • 0 — current — Current
  • 1 — default — Default
  • 2 — saved — Saved
  • 3 — supported — Supported capabilities
• -s, --save — save the attribute so that it persists through all power states and resets.

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🌈 GLOBAL OPTIONS 🌈

These are defined at the top-level nvme command, and they’re available to this subcommand too. Bestie, they’re global-global. 👑

• --dry-run — print the command that would be executed, but do not actually execute it.
• --no-ioctl-probing — disable probing for 64-bit IOCTL support.
• --no-retries — disable retry logic on transient errors.
• -o <fmt>, --output-format=<fmt> — set the reporting format to normal, tabular, 'json, or binary. Only one output format may be used at a time.
• --output-format-version=<version> — select the output format version. Version 1 uses the original field naming, while version 2 (default) provides more consistent and script-friendly field names. Other versions are rejected.
• --quiet — suppress informational messages. Errors are still reported, and --quiet cancels any --verbose for the library log level.
• --set-options=<key=value>[,<key=value>...] — set libnvme library options for this invocation. Supported keys are force-4k, mi-probe-enabled, test-base-dir and test-sysfs-dir.
• --timeout=<ms> — set the timeout for the command in milliseconds. infinite or -1 waits without a time limit (0xffffffff).
• -v, --verbose — increase the level of detail in the output. May be specified multiple times to further increase verbosity.

These options can also be set as machine-wide defaults in nvme-cli.conf(5). A command-line flag always overrides the file. No cap. 💖

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🎀 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

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👑 NVME 👑

Part of the nvme-user suite. ✨

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and that’s the whole vibe — sourced from the NVMe manual, dated 10/30/2026, page NVME-FEAT-PERFC(1). mwah 💋🎀