RFR: 8223438: add VirtualizationInformation JFR event

[Erik Gahlin]

Looks good.

Erik

> Hello, here is   the next webrev  with  adjusted coding following your 
> suggestion :
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8223438.2/ 
> <http://cr.openjdk.java.net/%7Embaesken/webrevs/8223438.2/>
>
> Best regards, Matthias
>
> *From:*Baesken, Matthias
> *Sent:* Donnerstag, 9. Mai 2019 09:03
> *To:* Erik Gahlin <erik.gahlin at oracle.com>; 
> 'hotspot-dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> *Subject:* RE: RFR: 8223438: add VirtualizationInformation JFR event
>
> Hi   Erik,  the virtualization names  are a set of fix names ,  so I 
> think we can do what you suggest .
>
> I just “borrowed” a bit  from  the code above …
>
> TRACE_REQUEST_FUNC(OSInformation) {
>
>   ResourceMark rm;
>
>   char* os_name = NEW_RESOURCE_ARRAY(char, 2048);
>
>   JfrOSInterface::os_version(&os_name);
>
>   EventOSInformation event;
>
>   event.set_osVersion(os_name);
>
>   event.commit();
>
> }
>
>    … where a ResourceMark + allocation is used (but  in jfrOSInterface 
> I  wonder about the  second allocation in  string.stream.as_string , 
> do we really need two here ?
>
> int JfrOSInterface::JfrOSInterfaceImpl::os_version(char** os_version) 
> const {
>
>   assert(os_version != NULL, "os_version pointer is NULL!");
>
>   stringStream os_ver_info;
>
>   os::print_os_info_brief(&os_ver_info);
>
>   *os_version = os_ver_info.as_string();       <--- second alloc
>
> Best regards, Matthias
>
> *From:*Erik Gahlin <erik.gahlin at oracle.com 
> <mailto:erik.gahlin at oracle.com>>
> *Sent:* Mittwoch, 8. Mai 2019 18:55
> *To:* Baesken, Matthias <matthias.baesken at sap.com 
> <mailto:matthias.baesken at sap.com>>; 'hotspot-dev at openjdk.java.net' 
> <hotspot-dev at openjdk.java.net <mailto:hotspot-dev at openjdk.java.net>>
> *Subject:* Re: RFR: 8223438: add VirtualizationInformation JFR event
>
> Hello,
>
> Looks good, but do we really need to allocate the name every time an 
> event is emitted in jfrPeriodic.cpp?
>
> It will not matter much from a performance perspective, but the code 
> would look cleaner if we would have.
>
> EventVirtualizationInformation event;
> event.set_name(JfrOSInterface::virtualization_name());
> event.commit();
>
> Thanks
> Erik
>
>     Hello, please review the following change .
>
>     It adds  a  simple VirtualizationInformation   event  to JFR .
>
>     The addition  to JFR  has been previously  proposed by Erik  when 
>     we discussed the enhancement of hs_error file output with
>     virtualization related information .
>
>     Bug/webrev :
>
>     https://bugs.openjdk.java.net/browse/JDK-8223438
>
>     http://cr.openjdk.java.net/~mbaesken/webrevs/8223438.1/
>     <http://cr.openjdk.java.net/%7Embaesken/webrevs/8223438.1/>
>
>     Thanks, Matthias
>