RFR: 8029630: Print thread id hex representation in error messages.

[Thomas Stüfe]

Hi Max,

I guess both would be fine: leave it at %x or add a new format specifier
macro. We also could deal with a better abstraction for thread ids in a
later change.

..Thomas

On Fri, Apr 3, 2015 at 5:55 PM, Max Ockner <max.ockner at oracle.com> wrote:

>  Thomas,
> Thanks for pointing out the flaw in thread.cpp. I will fix that.
> I originally looked for an abstraction but couldn't find one. If you think
> it would be better to create a new format specifier, then I will do that as
> well.
> Max
>
> On 4/3/2015 5:42 AM, Thomas Stüfe wrote:
>
> Hi Max,
>
>  Disclaimer: not a Reviewer.
>
>  In thread.cpp, the code prints the value of Thread* pointer, not a
> thread id. So the code was correct before.
>
>  That said, I find this pretty confusing, especially because it prints
> "tid=<this>". Maybe one should change this or throw it away.
>
>  --
>
>  As for vmError.cpp: this seems to be correct.
>
>  However, I would like to see this abstracted somehow, here is why:
>
>  The OpenJDK simply assumes thread id to be 32bit unsigned. This is not
> really portable and may bite us in the face (I am not sure if it already
> did, was not thread id 64bit on AIX? at least for kernel thread ids?).
>
>  If you use pthread_t to implement thread id, like many ports do, thread
> id may be anything - 64bit number, array, struct. POSIX leaves that open.
>
>  So, instead of a raw "%x", I propose as quick fix a format specifier for
> thread ids, e.g. "THREAD_ID_FORMAT". That way we could at least easily find
> all places where we print thread ids, if we later decide to change the type
> for thread ids.
>
>  Regards, Thomas
>
>
> On Thu, Apr 2, 2015 at 9:38 PM, Max Ockner <max.ockner at oracle.com> wrote:
>
>> Hello,
>> Please review this change:
>>
>> Bug:  https://bugs.openjdk.java.net/browse/JDK-8029630
>> Webrev: http://cr.openjdk.java.net/~mockner/8029630.2/
>> Summary: Existing error messages for vm crashes print the decimal
>> representation of the current thread id. The message format has been
>> changed to print the hex value of the thread id.
>>
>> Tested with jtreg runtime to make sure nothing was broken. I tested the
>> new functionality separately. I crashed the vm and examined the debugger
>> output to make sure the hexadecimal thread id printed in the error message
>> matched one of the threads listed by the debugger.
>>
>> Thanks,
>> Max
>>
>
>
>