>
>Should we make the change to determine just before it is needed (e.g. VM.info
>or hs_err log) at first?
>It is out of scope of this change, so I want to work as another issue if it is
>needed.
>
Hi ,
I think we better do not call into WMI , when writing an hs_err file .
Best regards, Matthias
-----Original Message-----
From: Yasumasa Suenaga <suen...@oss.nttdata.com>
Sent: Donnerstag, 13. August 2020 06:15
To: David Holmes <david.hol...@oracle.com>; Baesken, Matthias
<matthias.baes...@sap.com>; hotspot-runtime-...@openjdk.java.net;
build-dev@openjdk.java.net
Cc: Doerr, Martin <martin.do...@sap.com>
Subject: Re: PING: RFR: 8250598: Hyper-V is detected in spite of running on
host OS
On 2020/08/13 11:54, David Holmes wrote:
> On 13/08/2020 11:12 am, Yasumasa Suenaga wrote:
>> Hi Matthias, David,
>>
>> I measured startup benchmarks with `Measure-Command
>> {.\jdk\build\windows-x86_64-server-release\images\jdk\bin\java.exe
>> --version}` on PowerShell.
>>
>> * PC: Ryzen 3 3300X, 16GB memory
>> * OS: Windows 10 x64 (May 2020 Update)
>> * Java: jdk/jdk revision 60537
>> (Compiled by VS 2019 (16.7.0))
>>
>> * without patch
>> TotalMilliseconds : 70.2124
>> TotalMilliseconds : 64.4465
>> TotalMilliseconds : 59.0854
>> TotalMilliseconds : 68.0255
>> TotalMilliseconds : 72.6467
>> average : 66.8833
>>
>> * with webrev.01
>> TotalMilliseconds : 81.7185
>> TotalMilliseconds : 68.539
>> TotalMilliseconds : 85.7226
>> TotalMilliseconds : 72.6584
>> TotalMilliseconds : 75.6091
>> average : 76.84952
>>
>> Overhead of WMI seems to be +10ms in this case.
>
> Which is nearly 15%! Sorry but I just know Claes will be very unhappy if this
> were to go in as-is.
Should we make the change to determine just before it is needed (e.g. VM.info
or hs_err log) at first?
It is out of scope of this change, so I want to work as another issue if it is
needed.
Yasumasa
> David
> -----
>
>>
>> Yasumasa
>>
>>
>> On 2020/08/13 0:05, Baesken, Matthias wrote:
>>>> I understand that if the process runs on Xen on other hypervisor (e.g.
>>>> KVM), information for Xen would be set between 0x40000100 and 0x40010000.
>>>> Ok, I will not remove the loop in new webrev, and will add comment about
>>>> it.
>>>
>>> Hi Yasumasa , thanks !
>>>
>>> Regarding the WMI overhead , if you could get some more info on this it
>>> would be better to judge if it is perfectly okay or concerning .
>>>
>>> (I remember that I looked into it a couple of years ago , but decided not
>>> to use it in early VM startup ; but have to confess this was just based on
>>> a "gut feeling",
>>> No micro benchmarks )
>>>
>>> Best regards, Matthias
>>>
>>>
