diff mbox series

[v2] doc: update Linux core isolation guide

Message ID 20220517180856.1139-1-pbhagavatula@marvell.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series [v2] doc: update Linux core isolation guide |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/github-robot: build success github build: passed
ci/iol-aarch64-unit-testing success Testing PASS
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-intel-Functional success Functional Testing PASS
ci/iol-aarch64-compile-testing success Testing PASS
ci/iol-x86_64-unit-testing success Testing PASS
ci/iol-abi-testing success Testing PASS
ci/iol-x86_64-compile-testing success Testing PASS

Commit Message

Pavan Nikhilesh Bhagavatula May 17, 2022, 6:08 p.m. UTC 
  From: Pavan Nikhilesh <pbhagavatula@marvell.com>

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

Signed-off-by: Pavan Nikhilesh <pbhagavatula@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(-)

Comments

Stephen Hemminger May 17, 2022, 6:22 p.m. UTC | #1 
On Tue, 17 May 2022 23:38:55 +0530
<pbhagavatula@marvell.com> wrote:

> +
> +.. Note::
> +
> +         For more fine grained control over resource management and performance tuning one can look
> +         into ``Linux cgroups``.

Please provide a better link than just search terms:

Suggestions:

Cgroups uses cpusets.
https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/cpusets.html

Systemd provides standard API for system service contiainers.
https://www.freedesktop.org/software/systemd/man/systemd.exec.html
  - See CPUAffinity



See Also:
https://man7.org/linux/man-pages/man7/cpuset.7.html
https://www.suse.com/c/cpu-isolation-practical-example-part-5/
https://www.rcannings.com/systemd-core-isolation/
Pavan Nikhilesh Bhagavatula May 17, 2022, 6:32 p.m. UTC | #2 
> On Tue, 17 May 2022 23:38:55 +0530
> <pbhagavatula@marvell.com> wrote:
> 
> > +
> > +.. Note::
> > +
> > +         For more fine grained control over resource management and
> performance tuning one can look
> > +         into ``Linux cgroups``.
> 
> Please provide a better link than just search terms:
>

Sure, I will add the below mention links.

Thanks,
Pavan.
 
> Suggestions:
> 
> Cgroups uses cpusets.
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__www.kernel.org_doc_html_latest_admin-2Dguide_cgroup-
> 2Dv1_cpusets.html&d=DwICAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=E3SgYMjt
> KCMVsB-fmvgGV3o-g_fjLhk5Pupi9ijohpc&m=W4c3sgjcX-
> QYOzJv3083R9UxKOzobyP_wZgBG3KO3B6qRTgub_xwUZXA8Iu6tJVc&s=_D2z
> m10RTVVLAgXCM9_ZCdBqwgy5KmDgM1oS39b_ZOc&e=
> 
> Systemd provides standard API for system service contiainers.
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__www.freedesktop.org_software_systemd_man_systemd.exec.html&d
> =DwICAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=E3SgYMjtKCMVsB-fmvgGV3o-
> g_fjLhk5Pupi9ijohpc&m=W4c3sgjcX-
> QYOzJv3083R9UxKOzobyP_wZgBG3KO3B6qRTgub_xwUZXA8Iu6tJVc&s=DUY
> 1DqusOfcBDJdEbLXK4fKGT1mC6g7pSR9k4bUA8Cg&e=
>   - See CPUAffinity
> 
> 
> 
> See Also:
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__man7.org_linux_man-
> 2Dpages_man7_cpuset.7.html&d=DwICAg&c=nKjWec2b6R0mOyPaz7xtfQ&r
> =E3SgYMjtKCMVsB-fmvgGV3o-g_fjLhk5Pupi9ijohpc&m=W4c3sgjcX-
> QYOzJv3083R9UxKOzobyP_wZgBG3KO3B6qRTgub_xwUZXA8Iu6tJVc&s=JQe
> W8pniCghPjX7-Ek2Jte0mjAhDiUJqMOHKyD4Jxvg&e=
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__www.suse.com_c_cpu-2Disolation-2Dpractical-2Dexample-2Dpart-
> 2D5_&d=DwICAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=E3SgYMjtKCMVsB-
> fmvgGV3o-g_fjLhk5Pupi9ijohpc&m=W4c3sgjcX-
> QYOzJv3083R9UxKOzobyP_wZgBG3KO3B6qRTgub_xwUZXA8Iu6tJVc&s=QOs
> 65Ok6O0iO8XmijbcD_4RXwwkM9BroclTePWKiPco&e=
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__www.rcannings.com_systemd-2Dcore-
> 2Disolation_&d=DwICAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=E3SgYMjtKCMVs
> B-fmvgGV3o-g_fjLhk5Pupi9ijohpc&m=W4c3sgjcX-
> QYOzJv3083R9UxKOzobyP_wZgBG3KO3B6qRTgub_xwUZXA8Iu6tJVc&s=mQo
> JS4euMdCV2BI2UzGptDdICygMwBMZdJ6OWtjpRYA&e=
diff mbox series

Patch

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: