RFR: 8065331: Add JVM trace events for failed allocations

Jesper Wilhelmsson jesper.wilhelmsson at oracle.com
Wed Apr 8 17:26:53 UTC 2015


Looks good!
/Jesper

Marcus Larsson skrev den 8/4/15 17:05:
> Hi again,
>
> During offline discussions with Erik Helin we decided to skip the gc-attempt
> counter altogether, since this information had little value. Also, as the
> "Collect for allocation" event would always be accompanied by the (already
> existing) garbage collection events, this event is unnecessary and has been
> removed as well. Instead, to see allocations pending a particular GC, one can
> look at "Allocations requiring GC" events preceding the garbage collection event
> sent for that GC.
>
> New (significantly smaller) webrev:
> http://cr.openjdk.java.net/~mlarsson/8065331/webrev.02/
>
> Thanks,
> Marcus
>
>
> On 04/02/2015 02:55 AM, Marcus Larsson wrote:
>> Hi Jon,
>>
>> Thank you for looking at this.
>>
>> The way I intended the gc count information to be useful is to indicate
>> if/when allocations keep failing. Problematic allocations would then have a gc
>> count higher than 1. It's not really critical that this is the exact total, as
>> it's just an indication, so a partial GC count could work I guess. If you
>> think it would be better I can take a look at how I can reduce the CR by being
>> less precise with this counter.
>>
>> Thanks,
>> Marcus
>>
>> ----- Original Message -----
>> From: jon.masamitsu at oracle.com
>> To: hotspot-gc-dev at openjdk.java.net
>> Sent: Wednesday, 1 April, 2015 4:44:30 PM GMT +01:00 Amsterdam / Berlin / Bern
>> / Rome / Stockholm / Vienna
>> Subject: Re: RFR: 8065331: Add JVM trace events for failed allocations
>>
>> Marcus,
>>
>> These changes are rather extensive and the CR is rather thin
>> on details.  How will the GC count information be useful?
>> Is it critical that it be the total GC count for failed allocation?
>> Could some partial GC count that does not require such
>> extensive changes be almost as useful?
>>
>> Thanks.
>>
>> Jon
>>
>> On 3/30/2015 3:54 PM, Marcus Larsson wrote:
>>> Ping!
>>>
>>> ----- Original Message -----
>>> From: marcus.larsson at oracle.com
>>> To: hotspot-gc-dev at openjdk.java.net
>>> Sent: Tuesday, 24 March, 2015 7:35:08 AM GMT +01:00 Amsterdam / Berlin / Bern
>>> / Rome / Stockholm / Vienna
>>> Subject: RFR: 8065331: Add JVM trace events for failed allocations
>>>
>>> Hi,
>>>
>>> Please review the following patch adding new trace events for allocations
>>> requiring GC, and GCs triggered by allocation. See the JEP for a description
>>> of these two new events.
>>>
>>> CR:
>>> https://bugs.openjdk.java.net/browse/JDK-8065331
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~mlarsson/8065331/webrev.00/
>>>
>>> JEP:
>>> https://bugs.openjdk.java.net/browse/JDK-8060092
>>>
>>> Tests:
>>> jprt, jtreg
>>>
>>> Thanks,
>>> Marcus
>


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