Request for review: 8008546: G1: Wrong G1CONFIDENCEPERCENT results in GUARANTEE(VARIANCE() > -1.0) FAILED

Bengt Rutisson bengt.rutisson at oracle.com
Wed Feb 20 15:22:30 UTC 2013


Hi Vladimir,

Looks good!

(Adding back the hotspot-gc-dev mailing list.)

Thanks,
Bengt

On 2/20/13 4:16 PM, vladimir kempik wrote:
> Hi Bengt,
>
> Thanks for looking at this!
>
> Here is an updated webrev based on your feedback:
> http://cr.openjdk.java.net/~mcherkas/vladimir/8008546/webrev.01/
>   <http://cr.openjdk.java.net/%7Ebrutisso/8002144/webrev.01/>
>
> I applied what you suggested.
>
> Thanks,
> Vladimir.
> On 20.02.2013 17:54, Bengt Rutisson wrote:
>>
>> Hi Vladimir,
>>
>> This looks very similar to how we treat G1ReservePercent, so I think 
>> it looks good. An alternative would have been to check this earlier 
>> in the initialization phase and update the flag G1ConfidencePercent 
>> so that PrintFlagsFinal would have printed the actual value. But for 
>> consistency I think it looks good this way.
>>
>> I think you can change G1ConfidencePercent to be an uintx instead of 
>> intx (in g1_globals.hpp). In that case you don't need the second if 
>> statment since it can't be less than 0. It is also more consistent 
>> with G1ReservePercent which is an uintx.
>>
>> Thanks,
>> Bengt
>>
>> On 2/20/13 2:31 PM, vladimir kempik wrote:
>>> Hi all,
>>>
>>> Could I have a couple of reviews for this change?
>>>
>>> http://cr.openjdk.java.net/~mcherkas/vladimir/8008546/webrev.00/
>>>
>>> Input value for G1CONFIDENCEPERCENT wasn't checked before using. 
>>> This results in crash sometimes if -XX:+UseG1GC 
>>> -XX:G1ConfidencePercent=200 flags are used. Now checking the value 
>>> same way as it was done for G1ReservePercent. Increase to 0 if 
>>> negative, decrease to 100 if more than 100.
>>>
>>> Thanks,
>>> Vladimir
>>>
>>
>

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