[PATCH v2] doc: update Linux core isolation guide

pbhagavatula at marvell.com pbhagavatula at marvell.com
Tue May 17 20:08:55 CEST 2022


From: Pavan Nikhilesh <pbhagavatula at marvell.com>

Update Linux core isolation guide to include isolation from
timers, rcu processing and IRQs.

Signed-off-by: Pavan Nikhilesh <pbhagavatula at marvell.com>
---
 v2 Changes: 
 - Add references to the parameters used.
 - Add note about Linux cgroups.

 doc/guides/linux_gsg/enable_func.rst | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/doc/guides/linux_gsg/enable_func.rst b/doc/guides/linux_gsg/enable_func.rst
index 1df3ab0255..d6f3961da7 100644
--- a/doc/guides/linux_gsg/enable_func.rst
+++ b/doc/guides/linux_gsg/enable_func.rst
@@ -90,16 +90,28 @@ Using Linux Core Isolation to Reduce Context Switches
 -----------------------------------------------------
 
 While the threads used by a DPDK application are pinned to logical cores on the system,
-it is possible for the Linux scheduler to run other tasks on those cores also.
-To help prevent additional workloads from running on those cores,
-it is possible to use the ``isolcpus`` Linux kernel parameter to isolate them from the general Linux scheduler.
+it is possible for the Linux scheduler to run other tasks on those cores.
+To help prevent additional workloads, timers, rcu processing and IRQs from running on those cores, it is possible to use
+the Linux kernel parameters ``isolcpus``, ``nohz_full``, ``irqaffinity`` to isolate them from the general Linux scheduler tasks.
 
-For example, if DPDK applications are to run on logical cores 2, 4 and 6,
+For example, if a given CPU has 0-7 cores and DPDK applications are to run on logical cores 2, 4 and 6,
 the following should be added to the kernel parameter list:
 
 .. code-block:: console
 
-    isolcpus=2,4,6
+    isolcpus=2,4,6 nohz_full=2,4,6 irqaffinity=0,1,3,5,7
+
+.. Note::
+
+         More detailed information about the above parameters can be found at
+         https://www.kernel.org/doc/html/latest/timers/no_hz.html
+         https://www.kernel.org/doc/html/latest/core-api/irq/
+         https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
+
+.. Note::
+
+         For more fine grained control over resource management and performance tuning one can look
+         into ``Linux cgroups``.
 
 .. _High_Precision_Event_Timer:
 
-- 
2.25.1



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