]> git.karo-electronics.de Git - karo-tx-linux.git/blobdiff - Documentation/kernel-parameters.txt
Merge branch 'x86-bsp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[karo-tx-linux.git] / Documentation / kernel-parameters.txt
index f7cbe1d98cb4d36030451c2e72fe0a978151478f..5190f1706414b942587bac9dcc6386b0f08c691a 100644 (file)
@@ -2408,6 +2408,27 @@ 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.
@@ -2873,6 +2894,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        to facilitate early boot debugging.
                        See also Documentation/trace/events.txt
 
+       trace_options=[option-list]
+                       [FTRACE] Enable or disable tracer options at boot.
+                       The option-list is a comma delimited list of options
+                       that can be enabled or disabled just as if you were
+                       to echo the option name into
+
+                           /sys/kernel/debug/tracing/trace_options
+
+                       For example, to enable stacktrace option (to dump the
+                       stack trace of each event), add to the command line:
+
+                             trace_options=stacktrace
+
+                       See also Documentation/trace/ftrace.txt "trace options"
+                       section.
+
        transparent_hugepage=
                        [KNL]
                        Format: [always|madvise|never]