RFR (S) JDK-8149023: Event based tracing should cover safepoint begin and end

[David Holmes]

Hi David,

On 10/02/2016 1:45 AM, David Simms wrote:
> Greetings all,
>
> I have small request for review, for adding event based tracing to
> "SafepointSynchronize::begin()" and "end()"
>
> JBS: https://bugs.openjdk.java.net/browse/JDK-8149023
> Webrev: http://cr.openjdk.java.net/~dsimms/8149023/webrev0/

Repeating what I said in email for the public record ...

I'm always concerned about the overhead of tracing when it is not being 
used.

I'm also concerned that it is not obvious what gets executed when these 
events are created, destroyed or committed. We have to be sure there are 
no actions that might interfere with the safepoint protocol, or which 
might themselves introduce latency into the safepoint process.

A new comment is that the event.commit blocks seems highly repetitive in 
many cases - dare I suggest using a macro? :)

Thanks,
David

> Testing: built all platforms (RBT), local jtreg
>
> Cheers
> /David Simms