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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-12-03 08:16:28 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-03-26 08:04:48 -0700
commita488985851cf2facd2227bd982cc2c251df56268 (patch)
tree450d84d1fc01bd7997b651e47d2587fac5c6f085 /Documentation/kernel-parameters.txt
parent09c7b890622d72b5e004cc249bbe610e8b928ddf (diff)
rcu: Distinguish "rcuo" kthreads by RCU flavor
Currently, the per-no-CBs-CPU kthreads are named "rcuo" followed by the CPU number, for example, "rcuo". This is problematic given that there are either two or three RCU flavors, each of which gets a per-CPU kthread with exactly the same name. This commit therefore introduces a one-letter abbreviation for each RCU flavor, namely 'b' for RCU-bh, 'p' for RCU-preempt, and 's' for RCU-sched. This abbreviation is used to distinguish the "rcuo" kthreads, for example, for CPU 0 we would have "rcuob/0", "rcuop/0", and "rcuos/0". Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt7
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4609e81dbc37..a17ba16c8fc8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2461,9 +2461,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
In kernels built with CONFIG_RCU_NOCB_CPU=y, set
the specified list of CPUs to be no-callback CPUs.
Invocation of these CPUs' RCU callbacks will
- be offloaded to "rcuoN" kthreads created for
- that purpose. This reduces OS jitter on the
+ be offloaded to "rcuox/N" kthreads created for
+ that purpose, where "x" is "b" for RCU-bh, "p"
+ for RCU-preempt, and "s" for RCU-sched, and "N"
+ is the CPU number. This reduces OS jitter on the
offloaded CPUs, which can be useful for HPC and
+
real-time workloads. It can also improve energy
efficiency for asymmetric multiprocessors.