Re: [PATCH 3/3] check: add --print-start-done to enhance watchdogs

[Luis Chamberlain <mcgrof@kernel.org>]

On Mon, Feb 19, 2024 at 02:42:32PM +1100, Dave Chinner wrote:
> On Fri, Feb 16, 2024 at 10:18:59AM -0800, Luis Chamberlain wrote:
> > fstests specific watchdogs want to know when the full test suite will
> > start and end. Right now the kernel ring buffer can get augmented but we
> > can't know for sure if it was due to a test or some odd hardware issue
> > after fstests ran. This is specially true for systems left running tests in
> > loops in automation where we are not running things ourselves but rather just
> > get access to kernel logs, or for filesystem runner watdogs such as the one
> > in kdevops [0]. It is also often not easy to determine for sure based on
> > just logs when fstests check really has completed unless we have a
> > matching log of who spawned that test runner. Although we could keep track of
> > this ourselves by an annotation locally on the test runner, it is useful to
> > have independent tools which are not attached to the process which spawned
> > check to just peak into a system and verify the system's progress with
> > fstests by just using the kernel log. Keeping this in the test target kernel
> > ring buffer enables these use cases.
> > 
> > This is useful for example for filesyste checker specific watchdogs like the
> > one in kdevops so that the watchdog knows when to start hunting for crashes
> > based just on the kernel ring buffer, and so it also knows when the show is
> > over.
> 
> Why can't the runner that requires timing information in the
> kernel log just emit a message to the kernel log before it
> runs check and again immediately after completion of the check
> script?

That's exactly what is done today, it just seemed to me that since this
has been useful to a test runner now for years, it might make sense to
generalize this.
 
  Luis