the propagation of recent CPU-hotplug changes up
the rcu_node combining tree.
- rcutree.use_softirq= [KNL]
- If set to zero, move all RCU_SOFTIRQ processing to
- per-CPU rcuc kthreads. Defaults to a non-zero
- value, meaning that RCU_SOFTIRQ is used by default.
- Specify rcutree.use_softirq=0 to use rcuc kthreads.
-
- But note that CONFIG_PREEMPT_RT=y kernels disable
- this kernel boot parameter, forcibly setting it
- to zero.
-
- rcutree.rcu_fanout_exact= [KNL]
- Disable autobalancing of the rcu_node combining
- tree. This is used by rcutorture, and might
- possibly be useful for architectures having high
- cache-to-cache transfer latencies.
-
- rcutree.rcu_fanout_leaf= [KNL]
- Change the number of CPUs assigned to each
- leaf rcu_node structure. Useful for very
- large systems, which will choose the value 64,
- and for NUMA systems with large remote-access
- latencies, which will choose a value aligned
- with the appropriate hardware boundaries.
-
- rcutree.rcu_min_cached_objs= [KNL]
- Minimum number of objects which are cached and
- maintained per one CPU. Object size is equal
- to PAGE_SIZE. The cache allows to reduce the
- pressure to page allocator, also it makes the
- whole algorithm to behave better in low memory
- condition.
-
- rcutree.rcu_delay_page_cache_fill_msec= [KNL]
- Set the page-cache refill delay (in milliseconds)
- in response to low-memory conditions. The range
- of permitted values is in the range 0:100000.
-
rcutree.jiffies_till_first_fqs= [KNL]
Set delay from grace-period initialization to
first attempt to force quiescent states.
When RCU_NOCB_CPU is set, also adjust the
priority of NOCB callback kthreads.
- rcutree.rcu_divisor= [KNL]
- Set the shift-right count to use to compute
- the callback-invocation batch limit bl from
- the number of callbacks queued on this CPU.
- The result will be bounded below by the value of
- the rcutree.blimit kernel parameter. Every bl
- callbacks, the softirq handler will exit in
- order to allow the CPU to do other work.
-
- Please note that this callback-invocation batch
- limit applies only to non-offloaded callback
- invocation. Offloaded callbacks are instead
- invoked in the context of an rcuoc kthread, which
- scheduler will preempt as it does any other task.
-
rcutree.nocb_nobypass_lim_per_jiffy= [KNL]
On callback-offloaded (rcu_nocbs) CPUs,
RCU reduces the lock contention that would
the ->nocb_bypass queue. The definition of "too
many" is supplied by this kernel boot parameter.
- rcutree.rcu_nocb_gp_stride= [KNL]
- Set the number of NOCB callback kthreads in
- each group, which defaults to the square root
- of the number of CPUs. Larger numbers reduce
- the wakeup overhead on the global grace-period
- kthread, but increases that same overhead on
- each group's NOCB grace-period kthread.
-
rcutree.qhimark= [KNL]
Set threshold of queued RCU callbacks beyond which
batch limiting is disabled.
on rcutree.qhimark at boot time and to zero to
disable more aggressive help enlistment.
+ rcutree.rcu_delay_page_cache_fill_msec= [KNL]
+ Set the page-cache refill delay (in milliseconds)
+ in response to low-memory conditions. The range
+ of permitted values is in the range 0:100000.
+
+ rcutree.rcu_divisor= [KNL]
+ Set the shift-right count to use to compute
+ the callback-invocation batch limit bl from
+ the number of callbacks queued on this CPU.
+ The result will be bounded below by the value of
+ the rcutree.blimit kernel parameter. Every bl
+ callbacks, the softirq handler will exit in
+ order to allow the CPU to do other work.
+
+ Please note that this callback-invocation batch
+ limit applies only to non-offloaded callback
+ invocation. Offloaded callbacks are instead
+ invoked in the context of an rcuoc kthread, which
+ scheduler will preempt as it does any other task.
+
+ rcutree.rcu_fanout_exact= [KNL]
+ Disable autobalancing of the rcu_node combining
+ tree. This is used by rcutorture, and might
+ possibly be useful for architectures having high
+ cache-to-cache transfer latencies.
+
+ rcutree.rcu_fanout_leaf= [KNL]
+ Change the number of CPUs assigned to each
+ leaf rcu_node structure. Useful for very
+ large systems, which will choose the value 64,
+ and for NUMA systems with large remote-access
+ latencies, which will choose a value aligned
+ with the appropriate hardware boundaries.
+
+ rcutree.rcu_min_cached_objs= [KNL]
+ Minimum number of objects which are cached and
+ maintained per one CPU. Object size is equal
+ to PAGE_SIZE. The cache allows to reduce the
+ pressure to page allocator, also it makes the
+ whole algorithm to behave better in low memory
+ condition.
+
+ rcutree.rcu_nocb_gp_stride= [KNL]
+ Set the number of NOCB callback kthreads in
+ each group, which defaults to the square root
+ of the number of CPUs. Larger numbers reduce
+ the wakeup overhead on the global grace-period
+ kthread, but increases that same overhead on
+ each group's NOCB grace-period kthread.
+
rcutree.rcu_kick_kthreads= [KNL]
Cause the grace-period kthread to get an extra
wake_up() if it sleeps three times longer than
rcu_node tree with an eye towards determining
why a new grace period has not yet started.
+ rcutree.use_softirq= [KNL]
+ If set to zero, move all RCU_SOFTIRQ processing to
+ per-CPU rcuc kthreads. Defaults to a non-zero
+ value, meaning that RCU_SOFTIRQ is used by default.
+ Specify rcutree.use_softirq=0 to use rcuc kthreads.
+
+ But note that CONFIG_PREEMPT_RT=y kernels disable
+ this kernel boot parameter, forcibly setting it
+ to zero.
+
rcuscale.gp_async= [KNL]
Measure performance of asynchronous
grace-period primitives such as call_rcu().
projects / linux.git / commitdiff