RFR(S): 8210514: Obsolete SyncVerbose

coleen.phillimore at oracle.com coleen.phillimore at oracle.com
Fri Sep 7 22:16:15 UTC 2018

On 9/7/18 6:00 PM, Daniel D. Daugherty wrote:
> On 9/7/18 5:41 PM, coleen.phillimore at oracle.com wrote:
>> I think this looks good. I think as a future RFE we should add 
>> logging judiciously to this code and not preserve the logging that's 
>> already there.  The new logging for this code should look like the 
>> log_debug() etc calls and not with this distracting TEVENT macro.
> Just to clarify:
> That "distracting TEVENT macro" has an atomic event counter that is
> part of the logging output so that the person doing the debugging
> knows the sequence of TEVENT calls. When dealing with multi-threaded
> output, the system doesn't always issue the output in the same order
> in which the various threads generate it...

It doesn't use Atomic::add though, and this looks like it supresses 
output or only prints output if there's a collision in the increment?

- if ((v & (v - 1)) == 0) { \

And if you want to have logging in these places like this, I think you 
could use the thread id or have the counter.   And rename TEVENT to 
something like: LOG_EVENT.   And decide if these are the places that 
provide useful information to log.  I think these would be a useful RFE.


> Dan
>> Thanks,
>> Coleen
>> On 9/7/18 5:14 PM, Mikael Vidstedt wrote:
>>> Please review this change which obsoletes the SyncVerbose flag.
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8210514 
>>> <https://bugs.openjdk.java.net/browse/JDK-8210514>
>>> Webrev: 
>>> http://cr.openjdk.java.net/~mikael/webrevs/8210514/webrev.00/open/webrev/ 
>>> <http://cr.openjdk.java.net/~mikael/webrevs/8210514/webrev.00/open/webrev/> 
>>> * Background (from bug)
>>> The experimental SyncVerbose flag can in theory be used to produce 
>>> logging of some synchronization primitives. The flag was convenient 
>>> when the synchronization implementation was implemented and tuned a 
>>> long time ago.
>>> The SyncVerbose flag no longer serves the purpose it used to, and is 
>>> "Unstable" (the documentation of the flag says so explicitly). It 
>>> should be obsoleted and later removed.
>>> Testing: I’m running the normal tier1 testing (still in progress).
>>> Cheers,
>>> Mikael

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