RFR: 8219241: Provide basic virtualization related info in the hs_error file on linux/windows x86_64

[Doerr, Martin]

Hi everybody,

I think it makes sense to have the cupid available on all x86 platforms.
However, the current Windows version requires 64 bit because the ABI (calling convention) differs between 32 and 64 bit.
The linux version should work on all x86 platforms which support this kind of inline assembler.

So I suggest to make it compiler dependent:
One version for Visual Studio with implementation for 64 bit and TODO for 32 bit.
One version for other compilers which support such kind of inline assembler.

Best regards,
Martin


-----Original Message-----
From: hotspot-dev <hotspot-dev-bounces at openjdk.java.net> On Behalf Of Erik Gahlin
Sent: Freitag, 5. April 2019 01:22
To: hotspot-dev at openjdk.java.net
Subject: Re: RFR: 8219241: Provide basic virtualization related info in the hs_error file on linux/windows x86_64

I haven't looked at the code closely., but we definitely want this 
information in JFR, as a separate RFE of course. Any API that will make 
it easy to access the information later as char* is appreciated, i.e.

EventOSInformation event;
event.set_virtualization(Virtualization::name());
event.commit();

Thanks
Erik

> On 4/04/2019 10:35 pm, Baesken, Matthias wrote:
>>>
>>> On 4/04/2019 8:54 pm, Baesken, Matthias wrote:
>>>>>
>>>>> My remaining query is why we need the OS specific checks and code in
>>>>> os-cpu files? Isn't this just cpu specific? Even if a particular OS
>>>>> doesn't support virtualization, won't the cpuid query simply 
>>>>> report "no
>>>>> virtualization"?
>>>>>
>>>>
>>>> Hi David,  if you are referring to  these  os-cpu files  :
>>>>
>>>> src/hotspot/os_cpu/linux_x86/vm_version_linux_x86.cpp
>>>> src/hotspot/os_cpu/windows_x86/vm_version_windows_x86.cpp
>>>>
>>>> we have different coding available  because  I am not aware of a 
>>>> cross OS
>>> API/coding to get   the cpu id info.
>>>> That’s why different coding for LINUX/Windows.
>>>
>>> ?? But there's nothing in those added functions that is Linux specific
>>> or Windows specific! The only difference is the mechanism for doing
>>> "inline assembly" and that's compiler specific. So this should just use
>>> compiler based ifdefs in vm_version_x86.cpp.
>>>
>>
>> Hi David, I see your point.  But I thought we want to reduce the  
>> ifdefs and favor  putting code into the os or os/cpu specific  files .
>> But it is true , from a technical point  we could do using the 
>> compiler macros .
>
> I favour putting os-specific code in os-specific files over OS ifdefs 
> in shared files. But here we are talking about compiler-specific code 
> that is also CPU specific (not os specific). So compiler ifdefs in the 
> cpu files is the way to handle this.
>
> Thanks,
> David
>
>> Best regards, Matthias
>>