Re: What does "Execution timeout is: $test_timeout" mean?

Jonathan Wakely wrote:
> Hi,
>
> [...]
>
> If I set test_timeout in ~/.dejagnurc or site.exp then I do indeed see
> the value change. But it doesn't do anything. I can set test_timeout
> to 2 second, and tests that sleep for 20 seconds or more will still
> PASS and not timeout (as long as $tool_timeout is large enough).

Evidently, the GCC testsuite is overriding that setting.

> The docs added by that patch say that $test_timeout is "the amount of
> time (in seconds) to wait for a remote test to complete" which doesn't
> match my observations. Is it because I'm testing locally, not
> remotely? If that value only affects remote tests, why does DejaGnu
> print "Execution timeout is: $test_timeout" to the logs
> unconditionally? It's unhelpful (i.e. downright confusing) to log it
> if it's not actually relevant.
>
> DejaGnu *does* know about the "real" timeout, because the remote_exec
> proc in remote.exp has already handled it and logged it via this
> command:
>
>     verbose -log "Executing on $hostname: $program $pargs $inp $outp 
> (timeout = $timeout)" 2
>
> I see that in my logs, and the $timeout value is the one I've set via
> $tool_timeout and actually works. If I set that to a low value, my
> tests timeout and FAIL. That timeout is the total time for both
> compiling and running the test.
>
> When I use -v -v -v with dejagnu-1.6.1 and set GCC's tool_timeout=30
> and test_timeout=2 I see the output in the attached extract from the
> log. The lines beginning with ================ are printed by the test
> itself, showing it sleeps for 20 seconds. Despite DejaGnu telling me
> the execution timeout is 2, the test passes. Either the execution
> timeout is not used, or the timeout is not working.

DejaGnu seems to only implement one timeout at a time, so the use of 
GCC's tool_timeout (probably) overrides DejaGnu's own test_timeout.  The 
underlying Expect works this way, and DejaGnu does not currently select 
from the minimum of multiple timeouts.  Also, DejaGnu's timeouts are 
meant to catch hung tests, so they are reset whenever output arrives 
from the test case.  (That is probably not part of this issue here, but 
it is important to remember, especially since there are also places in 
DejaGnu where some number of timeouts are permitted to occur before an 
error is actually reported.)

> Could unix.exp stop logging that line unconditionally if it's not
> true?
>
> Is it supposed to be true? Is the timeout failing to fire? Is it not
> relevant for local tests?
>
> I'm very confused.

I am also confused, so I have added this to my list of future issues to 
address once I learn enough to understand (and document!) DejaGnu's 
remote testing code.


-- Jacob