Please review -XshowSettings a java launcher option.

[Kumar Srinivasan]

On 11/12/2010 11:59 AM, David Holmes wrote:
> Kumar Srinivasan said the following on 11/13/10 01:16:
>>>>> - ServerClassMachine() does not take into account -Xint 
>>>>> possibility (and will need updating for Tiered compilation)
>>>>
>>>> Absolutely when that becomes a reality.
>>>
>>> You overlooked the -Xint part. I believe you will report "client" 
>>> when -Xint is specified.
>>
>> On what class machine ? a server class ? in which case it reports 
>> "server" for me.
>
> Okay, I wasn't sure if the ServerClassMachine() logic actually 
> accounted for -Xint. I thought it did in which case it would return 
> false and so you would assume client. Returning "server" is just as 
> wrong here unless the intent is to simply show whether this is 
> considered a server class machine regardless of whether -client or 
> -Xint were specified. That said will -client cause 
> ServerClassMachine() to return false? I don't know what the ergo 
> policy logic does here:
>
>  switch(GetErgoPolicy()) {
>     case NEVER_SERVER_CLASS:
>       return JNI_FALSE;
>     case ALWAYS_SERVER_CLASS:
>       return JNI_TRUE;
>
> In any case the issue is what this value is supposed to show - if it 
> is just showing whether this is a server class machine, and that is 
> not affected by specifying -client or -Xint then okay, but that wasn't 
> completely clear to me - I would change:
>
> "Ergonomics Class (server or client): "
>
> to say
>
> "Ergonomics Machine Class (server or client): "

Yes the intention is to tell the user "Hey we think this is a Server 
Class Machine, but you are
running a client vm". I will change it to your wordings.

Kumar


>
>
>> It is incomplete!, that is why I have the disclaimer and proposed it 
>> as "-X" flag.
>> So that we can evolve this flag in future releases, and use jdk7 to 
>> get the feedback
>> from users on what they would like to see for settings.
>>
>>> (But that pretty much sums up the state of all our flags anyway: 
>>> -foo vs -Xfoo vs -XX:foo :( )
>>
>>
>> Yeh I know and I rest my case for this flag. ;-)
>> This is exactly why we need one interface to bring the whole Java 
>> setting story together.
>> We cannot tell our users/support personnel, SQE etc. to use different 
>> flags to get the Java and VM settings.
>
> Then I would suggest that in parallel with this we add another -XX 
> flag that takes a list of VM variables for which the final value 
> should be printed. -Xshowsettings would then add 
> -XX:PrintFlagValues=flag1,flag2 etc. Of course the launcher would not 
> have control over the output format in that case and the output would 
> not be consistent with what is proposed today (hence my reluctance to 
> pursue this part of the RFE today). But this way it would be easy for 
> the launcher to update the list of variables reported.
>
> David
>
>>
>> Thanks
>>
>> Kumar
>>>
>>> David
>>>
>>>>
>>>> Thanks
>>>>
>>>> Kumar
>>>>
>>>>>
>>>>> David
>>>>>
>>>>> Kumar Srinivasan said the following on 11/12/10 07:56:
>>>>>> Hi All,
>>>>>>
>>>>>> Please review the following:
>>>>>>
>>>>>> http://cr.openjdk.java.net/~ksrini/6452854/webrev.00/
>>>>>>
>>>>>> This will print all the known settings/properties/locales
>>>>>> supported and known  to Java, this has  been a long standing 
>>>>>> request.
>>>>>>
>>>>>> A sample output attached below.
>>>>>>
>>>>>> Note: the -X option specifically is being used so we can evolve 
>>>>>> this option
>>>>>> and add more useful information, in future versions of java.
>>>>>>
>>>>>> Thanks
>>>>>> Kumar
>>>>>>
>>>>>>
>>>>>>
>>>>
>>