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linux/Documentation/kernel-per-CPU-kthreads.txt

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kthread: Document ways of reducing OS jitter due to per-CPU kthreads The Linux kernel uses a number of per-CPU kthreads, any of which might contribute to OS jitter at any time. The usual approach to normal kthreads, namely to bind them to a "housekeeping" CPU, does not work with these kthreads because they cannot operate correctly if moved to some other CPU. This commit therefore lists ways of controlling OS jitter from the Linux kernel's per-CPU kthreads. It also lists some ways of diagnosing excessive jitter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Christoph Lameter <cl@linux.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Olivier Baetz <olivier.baetz@novasparks.com> Cc: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de>
2013-04-11 08:07:11 -07:00
kthread: Add kworker kthreads to OS-jitter documentation The kworker workqueue kthreads can also contribute to OS jitter. The amount of jitter depends on their use, so this commit adds documentation on avoiding OS jitter due to workqueue use. Reported-by: Jonathan Clairembault <jonathan.clairembault@novasparks.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-04-30 10:48:35 -07:00
Documentation/kernel-per-CPU-kthreads.txt: Workqueue affinity This commit documents the ability to apply CPU affinity to WQ_SYSFS workqueues, thus offloading them from the desired worker CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Tejun Heo <tj@kernel.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-12 11:12:37 -08:00
kthread: Add kworker kthreads to OS-jitter documentation The kworker workqueue kthreads can also contribute to OS jitter. The amount of jitter depends on their use, so this commit adds documentation on avoiding OS jitter due to workqueue use. Reported-by: Jonathan Clairembault <jonathan.clairembault@novasparks.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-04-30 10:48:35 -07:00
documentation: Update based on on-demand vmstat workers Now that the on-demand vmstat workers commit is in mainline, it is possible to eliminate vmstat_update()-induced OS jitter. This commit updates the documentation accordingly. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-24 22:24:14 -08:00
kthread: Add pointer to vmstat-avoidance patch Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-09-10 08:26:09 -07:00
documentation: Update per-CPU kthreads documentation Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-25 11:48:18 -08:00
kthread: Add kworker kthreads to OS-jitter documentation The kworker workqueue kthreads can also contribute to OS jitter. The amount of jitter depends on their use, so this commit adds documentation on avoiding OS jitter due to workqueue use. Reported-by: Jonathan Clairembault <jonathan.clairembault@novasparks.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-04-30 10:48:35 -07:00
documentation: Update per-CPU kthreads documentation Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-25 11:48:18 -08:00
kthread: Add kworker kthreads to OS-jitter documentation The kworker workqueue kthreads can also contribute to OS jitter. The amount of jitter depends on their use, so this commit adds documentation on avoiding OS jitter due to workqueue use. Reported-by: Jonathan Clairembault <jonathan.clairembault@novasparks.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-04-30 10:48:35 -07:00
documentation: Update per-CPU kthreads documentation Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-25 11:48:18 -08:00
kthread: Add kworker kthreads to OS-jitter documentation The kworker workqueue kthreads can also contribute to OS jitter. The amount of jitter depends on their use, so this commit adds documentation on avoiding OS jitter due to workqueue use. Reported-by: Jonathan Clairembault <jonathan.clairembault@novasparks.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-04-30 10:48:35 -07:00
kthread: Document ways of reducing OS jitter due to per-CPU kthreads The Linux kernel uses a number of per-CPU kthreads, any of which might contribute to OS jitter at any time. The usual approach to normal kthreads, namely to bind them to a "housekeeping" CPU, does not work with these kthreads because they cannot operate correctly if moved to some other CPU. This commit therefore lists ways of controlling OS jitter from the Linux kernel's per-CPU kthreads. It also lists some ways of diagnosing excessive jitter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Christoph Lameter <cl@linux.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Olivier Baetz <olivier.baetz@novasparks.com> Cc: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de>
2013-04-11 08:07:11 -07:00
rcu: Fix Documentation typo 'CONFIG_RCU_NOCB_CPUS' Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2013-05-28 09:52:05 +02:00
kthread: Document ways of reducing OS jitter due to per-CPU kthreads The Linux kernel uses a number of per-CPU kthreads, any of which might contribute to OS jitter at any time. The usual approach to normal kthreads, namely to bind them to a "housekeeping" CPU, does not work with these kthreads because they cannot operate correctly if moved to some other CPU. This commit therefore lists ways of controlling OS jitter from the Linux kernel's per-CPU kthreads. It also lists some ways of diagnosing excessive jitter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Christoph Lameter <cl@linux.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Olivier Baetz <olivier.baetz@novasparks.com> Cc: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de>
2013-04-11 08:07:11 -07:00
documentation: Update per-CPU kthreads documentation Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-25 11:48:18 -08:00
kthread: Document ways of reducing OS jitter due to per-CPU kthreads The Linux kernel uses a number of per-CPU kthreads, any of which might contribute to OS jitter at any time. The usual approach to normal kthreads, namely to bind them to a "housekeeping" CPU, does not work with these kthreads because they cannot operate correctly if moved to some other CPU. This commit therefore lists ways of controlling OS jitter from the Linux kernel's per-CPU kthreads. It also lists some ways of diagnosing excessive jitter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Christoph Lameter <cl@linux.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Olivier Baetz <olivier.baetz@novasparks.com> Cc: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de>
2013-04-11 08:07:11 -07:00
documentation: Update per-CPU kthreads documentation Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2015-01-25 11:48:18 -08:00
kthread: Document ways of reducing OS jitter due to per-CPU kthreads The Linux kernel uses a number of per-CPU kthreads, any of which might contribute to OS jitter at any time. The usual approach to normal kthreads, namely to bind them to a "housekeeping" CPU, does not work with these kthreads because they cannot operate correctly if moved to some other CPU. This commit therefore lists ways of controlling OS jitter from the Linux kernel's per-CPU kthreads. It also lists some ways of diagnosing excessive jitter. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Christoph Lameter <cl@linux.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Olivier Baetz <olivier.baetz@novasparks.com> Cc: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de>
2013-04-11 08:07:11 -07:00