On 7/26/2023 6:59 AM, Richard Cochran wrote:
On Tue, Jul 25, 2023 at 09:34:00AM +0200, Lukasz Plachno wrote:
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.
Nice to have an updated man page, but I have a few comments...
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:
Would look better with a blank line here...
+.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
... and here, to delineate the message. Also, message could be
indented for clarity.
+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 {}
chrt with `-r` ?
Round robin, really?
Did you mean `-f` instead?
Typically I use -f aka --fifo with priority 75 (as normal threaded
ISRs run with priority 50)
Also, can make the shell examples look like the one under LONG OPTIONS?
.RS
\f(CW\-\-clientOnly 1 \-\-clientOnly=1\fP
.RE
This renders like this...
Each and every configuration file option (see below) may also appear as
a "long" style command line argument. For example, the clientOnly op‐
tion may be set using either of these two forms.
--clientOnly 1 --clientOnly=1
Option values given on the command line override values in the global
section of the configuration file.
Thanks,
Richard
I will send v6 with all mentioned changes.
Thanks,
Łukasz
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