RFR: 8065331: Add JVM trace events for failed allocations

Marcus Larsson marcus.larsson at oracle.com
Wed Apr 8 15:48:20 UTC 2015


On 04/08/2015 05:13 PM, Erik Helin wrote:
> On 2015-04-08, Marcus Larsson wrote:
>> 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/
> Looks good to me, Reviewed.
>
> Thanks,
> Erik

Thank you Erik!

Marcus

>> 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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