Request for Reviews(M): 7092905: C2: Keep track of the number of dead nodes

[Vladimir Ivanov]

Small addition to the last paragraph: if the compiler log isn't 
available, it's still useful to get this type of warnings.

Best regards,
Vladimir Ivanov

On 10/31/12 6:17 PM, Vladimir Ivanov wrote:
> John,
>
> Thanks for the clarification.
>
> I agree that compiler's <task> section is the best fit for such info.
> What I would like to see is clearer format and denser data
> representation, so it isn't burdensome to parse it by automatic tools
> (like LogCompilation).
>
> But I still have one unclear point. It's more methodological and relates
> to VM logging in general. Do we have a habit to look for warnings in
> compilation logs? :-)
>
> When a warning is issued during node count verification step, it doesn't
> occur on console. I would duplicate it both on console & in the log
> then. But, I rely on my own habits here - if I request such checks
> explicitly, I would like to easily see them.
>
> Best regards,
> Vladimir Ivanov
>
> On 10/30/12 11:27 PM, John Rose wrote:
>> On Oct 30, 2012, at 7:48 AM, Vladimir Ivanov wrote:
>>
>>> Regarding the currently published version, I think that logging part can
>>> be improved further.
>>
>> Those are good suggestions, Vladimir.
>>
>>> The general question is: do you intentionally print this info into XML
>>> compiler log? Why don't you use tty instead? All the messages will
>>> appear on console and will be duplicated in <tty> section in XML log
>>> anyway and you don't need to bother too much about the format.
>>
>> Each compiler thread has a separate log section, divided in the <task>s
>> executed by that thread.
>>
>> The main <tty> log is global, and intended for globally serialized
>> runtime events, such as deoptimizations or GCs or tty->print stuff.
>>
>> Meanwhile, the compiler (in one more more threads) runs asynchronously
>> to all the Java application threads.  So it gets a separate log.
>>
>> If an interesting event occurs within the time-sequence of a compiler
>> task, it should be logged in that compiler thread's C->log.
>>
>> When the JVM exits, all the extra compiler logs are catted together onto
>> the end of the main log's output file.
>>
>> — John