On Wed, 1 Jul 2026 11:04:07 +0100
David Laight [off-list ref] wrote:

I thought it was just used to do a pid->string lookup when you run 'cat trace'.
But then I found the code that lets userspace read the table....
I guess the latter is used by the userspace code that reads the raw trace buffer.

Yes, trace-cmd uses it.

(I found some instructions that did it that way, the output was unparseable
when tracing things that are happening on multiple cpu.)
The userspace code could probably be given comm[] for all the running
processes and those that exited while tracing_on() set.
(I didn't see anything that would clear the table when the trace buffer
was cleared.)

Well, that would break trace-cmd. As reading the raw buffers clears the
trace, and trace-cmd reads the saved_cmdlines file *after* it reads the
trace, as during the trace it gets populated.

-- Steve