DPDK patches and discussions
 help / color / mirror / Atom feed
* [PATCH 1/2] doc: add note about CPU 0
@ 2024-07-18 18:43 Stephen Hemminger
  2024-07-18 18:43 ` [PATCH 2/2] doc: remove use of -n 4 option in documentation Stephen Hemminger
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Stephen Hemminger @ 2024-07-18 18:43 UTC (permalink / raw)
  To: dev; +Cc: Stephen Hemminger

On Linux (and probably BSD), CPU 0 can not be fully isolated
because it receives timer interrupts and is used for other
kernel related functions. The DPDK documentation should
be updated to tell users to avoid polling on that CPU.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 doc/guides/linux_gsg/enable_func.rst | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/doc/guides/linux_gsg/enable_func.rst b/doc/guides/linux_gsg/enable_func.rst
index 5511640cb8..dc33ffc718 100644
--- a/doc/guides/linux_gsg/enable_func.rst
+++ b/doc/guides/linux_gsg/enable_func.rst
@@ -131,9 +131,14 @@ 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.
 
+.. note::
+
+    It is not recommended to use CPU core 0 for DPDK polling applications
+    because it can not be isolated from other system and kernel activity.
+
 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:
+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
 
-- 
2.43.0


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2024-07-31  8:32 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-07-18 18:43 [PATCH 1/2] doc: add note about CPU 0 Stephen Hemminger
2024-07-18 18:43 ` [PATCH 2/2] doc: remove use of -n 4 option in documentation Stephen Hemminger
2024-07-19  8:15   ` Bruce Richardson
2024-07-19 13:37   ` Jack Bond-Preston
2024-07-29 19:59 ` [PATCH 1/2] doc: add note about CPU 0 Thomas Monjalon
2024-07-31  4:38 ` [PATCH v2 " Stephen Hemminger
2024-07-31  4:38   ` [PATCH v2 2/2] doc: remove use of -n 4 option in documentation Stephen Hemminger
2024-07-31  8:16     ` Thomas Monjalon

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).