From 7896180a70a7e978eb0cdb8476e190555b55f225 Mon Sep 17 00:00:00 2001 From: Vincent Fu Date: Mon, 18 May 2020 13:50:53 -0400 Subject: [PATCH] docs: update cmdprio_percentage with note about root user The io_uring/libaio cmdprio_percentage option can only be used when fio is run from the root user account because IOs are submitted with IO priority class IOPRIO_CLASS_RT. Note in the documentation that fio must be run from the root account to use this option. Signed-off-by: Vincent Fu --- HOWTO | 3 ++- fio.1 | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/HOWTO b/HOWTO index 430c7b62..cd628552 100644 --- a/HOWTO +++ b/HOWTO @@ -2040,7 +2040,8 @@ with the caveat that when used on the command line, they must come after the the priority bit. Non-read I/O is likely unaffected by ``cmdprio_percentage``. This option cannot be used with the `prio` or `prioclass` options. For this option to set the priority bit properly, NCQ priority must be supported and - enabled and :option:`direct`\=1 option must be used. + enabled and :option:`direct`\=1 option must be used. fio must also be run as + the root user. .. option:: fixedbufs : [io_uring] diff --git a/fio.1 b/fio.1 index a2379f98..9e9e1b1a 100644 --- a/fio.1 +++ b/fio.1 @@ -1806,7 +1806,8 @@ Set the percentage of I/O that will be issued with higher priority by setting the priority bit. Non-read I/O is likely unaffected by ``cmdprio_percentage``. This option cannot be used with the `prio` or `prioclass` options. For this option to set the priority bit properly, NCQ priority must be supported and -enabled and `direct=1' option must be used. +enabled and `direct=1' option must be used. fio must also be run as the root +user. .TP .BI (io_uring)fixedbufs If fio is asked to do direct IO, then Linux will map pages for each IO call, and -- 2.25.1