Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-3.10.git] / Documentation / kernel-parameters.txt
index 2b48c52..03d1251 100644 (file)
@@ -2394,6 +2394,27 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        ramdisk_size=   [RAM] Sizes of RAM disks in kilobytes
                        See Documentation/blockdev/ramdisk.txt.
 
+       rcu_nocbs=      [KNL,BOOT]
+                       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
+                       offloaded CPUs, which can be useful for HPC and
+                       real-time workloads.  It can also improve energy
+                       efficiency for asymmetric multiprocessors.
+
+       rcu_nocbs_poll  [KNL,BOOT]
+                       Rather than requiring that offloaded CPUs
+                       (specified by rcu_nocbs= above) explicitly
+                       awaken the corresponding "rcuoN" kthreads,
+                       make these kthreads poll for callbacks.
+                       This improves the real-time response for the
+                       offloaded CPUs by relieving them of the need to
+                       wake up the corresponding kthread, but degrades
+                       energy efficiency by requiring that the kthreads
+                       periodically wake up to do the polling.
+
        rcutree.blimit= [KNL,BOOT]
                        Set maximum number of finished RCU callbacks to process
                        in one batch.