[tip: core/rcu] doc: Document rcuperf's module parameters

[tip: core/rcu] doc: Document rcuperf's module parameters

[tip-bot2 for Paul E. McKenney]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     847dd70aa971a67b4dfdb8f131428dfb90d88714
Gitweb:        https://git.kernel.org/tip/847dd70aa971a67b4dfdb8f131428dfb90d88714
Author:        Paul E. McKenney <paulmck@kernel.org>
AuthorDate:    Fri, 29 May 2020 14:24:03 -07:00
Committer:     Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Mon, 29 Jun 2020 12:00:45 -07:00

doc: Document rcuperf's module parameters

This commit adds documentation for the rcuperf module parameters.

Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 36 ++++++++++++++++-
 1 file changed, 36 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index fb95fad..20cd00b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4407,6 +4407,42 @@
 			      reboot_cpu is s[mp]#### with #### being the processor
 					to be used for rebooting.
 
+	refperf.holdoff= [KNL]
+			Set test-start holdoff period.  The purpose of
+			this parameter is to delay the start of the
+			test until boot completes in order to avoid
+			interference.
+
+	refperf.loops= [KNL]
+			Set the number of loops over the synchronization
+			primitive under test.  Increasing this number
+			reduces noise due to loop start/end overhead,
+			but the default has already reduced the per-pass
+			noise to a handful of picoseconds on ca. 2020
+			x86 laptops.
+
+	refperf.nreaders= [KNL]
+			Set number of readers.  The default value of -1
+			selects N, where N is roughly 75% of the number
+			of CPUs.  A value of zero is an interesting choice.
+
+	refperf.nruns= [KNL]
+			Set number of runs, each of which is dumped onto
+			the console log.
+
+	refperf.readdelay= [KNL]
+			Set the read-side critical-section duration,
+			measured in microseconds.
+
+	refperf.shutdown= [KNL]
+			Shut down the system at the end of the performance
+			test.  This defaults to 1 (shut it down) when
+			rcuperf is built into the kernel and to 0 (leave
+			it running) when rcuperf is built as a module.
+
+	refperf.verbose= [KNL]
+			Enable additional printk() statements.
+
 	relax_domain_level=
 			[KNL, SMP] Set scheduler's default relax_domain_level.
 			See Documentation/admin-guide/cgroup-v1/cpusets.rst.