Re: [PATCH DejaGNU/GCC 0/1] Support per-test execution timeout factor

[Richard Sandiford]

"Maciej W. Rozycki" <macro@embecosm.com> writes:
> On Wed, 3 Jan 2024, Hans-Peter Nilsson wrote:
>
>> >  The test execution timeout is different from the tool execution timeout 
>> > where it is GCC execution that is being guarded against taking excessive 
>> > amount of time on the test host rather than the resulting test case 
>> > executable run on the target afterwards, as concerned here.  GCC already 
>> > has a `dg-timeout-factor' setting for the tool execution timeout, but has 
>> > no means to increase the test execution timeout.  The GCC side of these 
>> > changes adds a corresponding `dg-test-timeout-factor' setting.
>> 
>> Hmm.  I think it would be more correct to emphasize that the 
>> existing dg-timeout-factor affects both the tool execution *and* 
>> the test execution, whereas your new dg-test-timeout-factor only 
>> affects the test execution.  (And still measured on the host.)
>
>  Not really, `dg-timeout-factor' is only applied to tool execution and it 
> doesn't affect test execution.  Timeout value reporting used to be limited 
> in DejaGNU, but you can enable it easily now by adding the DejaGNU patch 
> series referred in the cover letter and see that `dg-timeout-factor' is 
> ignored for test execution.
>
>> Usually the compilation time is close to 0, so is this based on 
>> an actual need more than an itchy "wart"?
>> 
>> Or did I miss something?
>
>  Compilation is usually quite fast, but this is not always the case.  If 
> you look at the tests that do use `dg-timeout-factor' in GCC, and some 
> commits that added the setting, then you ought to find actual use cases.  
> I saw at least one such a test that takes an awful lot of time here on a 
> reasonably fast host machine and still passes where GCC has been built 
> with optimisation enabled, but does time out in the compilation phase if 
> the compiler has been built at -O0 for debugging purposes.  I'd have to 
> chase it though if you couldn't find it as I haven't written the name 
> down.

Sounds like it could be the infamous gcc.c-torture/compile/20001226-1.c :)

Richard

>  So yes, `dg-timeout-factor' does have its use, but it is different from 
> that of `dg-test-timeout-factor', hence the need for a separate setting.
>
>   Maciej