RFR (XS) 8213992: Rename and make DieOnSafepointTimeout the diagnostic option

[David Holmes]

Okay I guess we're redefining what "diagnostic" means :)

Cheers,
David

On 21/11/2018 2:17 am, Aleksey Shipilev wrote:
> On 11/19/18 3:43 PM, Daniel D. Daugherty wrote:
>> On 11/19/18 6:23 AM, Aleksey Shipilev wrote:
>>> On 11/19/18 6:08 AM, David Holmes wrote:
>>>>> David suggested making the option "product", but I don't like it very much: "product" option
>>>>> suggests this is a production-grade feature and it comes with expectations of support, which is
>>>>> interesting in itself when product feature crashes the VM. "diagnostic" keeps this mode
>>>>> available in
>>>>> product builds without the attached notion of support. Users that want fail-fast VM crash can then
>>>>> use that option on "we know what we are doing" basis.
>>>> I feel a little uncomfortable that "diagnostic" is being used as a synonym for "unsupported
>>>> product". If you really want to fail-fast in production then you're looking for a production flag
>>>> not a "diagnostic" one IMHO. I won't fight it but I'd like to know what others think.
>>> Yup, let's hear it. I don't want to bikeshed this too much :)
>>
>> If I was doing the work on this bug, I would have made it a diagnostic option
>> also. I have a bias towards adding options as diagnostic for two reasons:
>>
>> 1) Easier to get rid of the option if it's a bad idea.
>> 2) You have to use the '-XX:UnlockDiagnosticVMOption' option to use it
>>     which makes unintentional use more difficult.
> 
> Thanks. No further comments? David, are you happy? I am pushing this:
> 
> diff -r 0811cc0ab16e src/hotspot/share/runtime/globals.hpp
> --- a/src/hotspot/share/runtime/globals.hpp     Tue Nov 20 16:18:12 2018 +0100
> +++ b/src/hotspot/share/runtime/globals.hpp     Tue Nov 20 17:17:35 2018 +0100
> @@ -496,12 +496,12 @@
>                                                                               \
>     product(bool, SafepointTimeout, false,                                    \
>             "Time out and warn or fail after SafepointTimeoutDelay "          \
>             "milliseconds if failed to reach safepoint")                      \
>                                                                               \
> -  develop(bool, DieOnSafepointTimeout, false,                               \
> -          "Die upon failure to reach safepoint (see SafepointTimeout)")     \
> +  diagnostic(bool, AbortVMOnSafepointTimeout, false,                        \
> +          "Abort upon failure to reach safepoint (see SafepointTimeout)")   \
>                                                                               \
>     /* 50 retries * (5 * current_retry_count) millis = ~6.375 seconds */      \
>     /* typically, at most a few retries are needed                    */      \
>     product(intx, SuspendRetryCount, 50,                                      \
>             "Maximum retry count for an external suspend request")            \
> diff -r 0811cc0ab16e src/hotspot/share/runtime/safepoint.cpp
> --- a/src/hotspot/share/runtime/safepoint.cpp   Tue Nov 20 16:18:12 2018 +0100
> +++ b/src/hotspot/share/runtime/safepoint.cpp   Tue Nov 20 17:17:35 2018 +0100
> @@ -976,13 +976,13 @@
>         }
>         ls.print_cr("# SafepointSynchronize::begin: (End of list)");
>       }
>     }
> 
> -  // To debug the long safepoint, specify both DieOnSafepointTimeout &
> +  // To debug the long safepoint, specify both AbortVMOnSafepointTimeout &
>     // ShowMessageBoxOnError.
> -  if (DieOnSafepointTimeout) {
> +  if (AbortVMOnSafepointTimeout) {
>       fatal("Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.",
>             SafepointTimeoutDelay, VMThread::vm_safepoint_description());
>     }
>   }
> 
> 
> Thanks,
> -Aleksey
> 
>