As tx timestamp timeout is something multiple users encounter,
provide information for configuring kthread priorities in manual
for ptp4l where tx_timestamp_timeout is already described.
Signed-off-by: Lukasz Plachno <lukasz.plac...@intel.com>
---
ptp4l.8 | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/ptp4l.8 b/ptp4l.8
index 09ff108af102..a8d6efada41b 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -1032,6 +1032,38 @@ to maintain the correct offset between UTC and PTP
times. See
.BR phc2sys (8)
manual page for more details.
+.SH KTHREAD PRIORITY
+
+In case of following log:
+.br
+.I timed out while polling for tx timestamp
+.I increasing tx_timestamp_timeout or increasing
+.I kworker priority may correct this issue,
+.I but a driver bug likely causes it
+.br
+one of possible causes is kworker processing timestamps being starved,
+user might try manually increasing the priority of the kworker.
+
+Usually drivers use kworker created by PTP stack in Linux kernel,
+those kworkers are named:
+.I ptp<decimal number of clock>
+,
+user can manually bump the priority of the kworker process using chrt
+.br
+Example:
+.br
+.I pgrep \-f "ptp[0-9]+" | xargs \-I {} sudo chrt \-r \-\-pid 30 {}
+
+Intel ice driver may create multiple kworkers for one physical NIC and
+names those processes differently.
+.br
+Example for Intel E810 card:
+.br
+.I pgrep \-f ice-ptp | xargs \-I {} sudo chrt \-r \-\-pid 30 {}
+
+Assigning priority needs careful consideration as assigning too high
+priority to any task might make system unstable.
+
.SH SEE ALSO
.BR pmc (8),
.BR phc2sys (8)
--
2.34.1
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