RFR: 7194254 jstack reports wrong thread priorities

[David Holmes]

I've updated the fix to include the missing/extra newlines in the thread 
listing that was reported. Seems to be okay now for:
- G1
- CMS
- ParNew
- Serial (trivially so as there is no output :) )

New Webrev at:

http://cr.openjdk.java.net/~dholmes/7194254/webrev/

(Sorry I messed up the versioning of the webrev.)

Now the repos are open again could I please get an additional reviewer 
from runtime or serviceability so I can push this to hotspot-rt.

Thanks,
David


On 7/09/2012 7:14 PM, David Holmes wrote:
> On 7/09/2012 6:21 PM, Dmytro Sheyko wrote:
>> David,
>>
>> Maybe it makes sense to do some little corrections in format specifiers:
>>
>> st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
>> if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
>> st->print("prio=" INT32_FORMAT " ",
>> java_lang_Thread::priority(thread_oop));
>>
>> instead of
>>
>> st->print("#%ld ", java_lang_Thread::thread_id(thread_oop));
>> if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
>> st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
>
> I confused myself over the correctness of %ld versus your original %llx
> - sorry. The %d is fine and is used elsewhere when printing the priority.
>
> Webrev updated at same location.
>
> Thanks,
> David
>
>> Thanks,
>> Dmytro
>>
>>
>> > Date: Fri, 7 Sep 2012 16:54:32 +1000
>> > From: david.holmes at oracle.com
>> > To: hotspot-dev at openjdk.java.net
>> > CC: dmytro_sheyko at hotmail.com; serviceability-dev at openjdk.java.net
>> > Subject: RFR: 7194254 jstack reports wrong thread priorities
>> >
>> > This is a formal request for review for the patch contributed by Dymtro
>> > Sheyko as discussed previously here:
>> >
>> >
>> http://mail.openjdk.java.net/pipermail/hotspot-dev/2012-August/006376.html
>>
>> >
>> > I am one reviewer of course.
>> >
>> > The webrev is here:
>> >
>> > http://cr.openjdk.java.net/~dholmes/7194254/webrev.v1/
>> >
>> > The fix has two components:
>> >
>> > 1. It fixes a bug in os::get_priority that assumed a more positive
>> > integer was always higher priority than a less positive one.
>> >
>> > 2. It addresses the problem that os::get_priority is often inexact when
>> > desiring the Java thread priority (because the mapping from Java
>> > priority to OS priority is often M:1) by not using it in
>> > Threads::print_on. Instead Threads::print_on will always report the
>> > native OS priority, and JavaThread::print_on() will print the
>> > java.lang.Thread.getId() value together with the
>> > java.lang.Thread.getPriority() value.
>> >
>> > This change in output affects all stackdumps including crash logs and
>> > thread dumps (including those shown by jstack).
>> >
>> > There is also a test program to check jstack output. I'll be doing some
>> > additional validation while the RFR is in progress.
>> >
>> > Thanks,
>> > David