[RFR] 8202427: Enhance os::print_memory_info on Windows

[Baesken, Matthias]

Hi Martin,  thanks for your input .
I add  hotspot-runtime-dev  .

> 
> I wonder if we really need the sizes in kB in addition to MB. Maybe other
> reviewers would like to comment on this, too.
>

We could also  just print  the  MB  value  , let's see what other think.
Another option might be to have a flexible output   (kB for  smaller  memory values , MB   (or GB)  for larger ) ?

Best regards, Matthias


> -----Original Message-----
> From: Doerr, Martin
> Sent: Mittwoch, 2. Mai 2018 12:53
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-
> dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: RE: [RFR] 8202427: Enhance os::print_memory_info on Windows
> 
> Hi Matthias,
> 
> looks like a nice enhancement. We can get substantially more information.
> 
> I wonder if we really need the sizes in kB in addition to MB. Maybe other
> reviewers would like to comment on this, too.
> 
> We should have line breaks.
> 
> Best regards,
> Martin
> 
> 
> -----Original Message-----
> From: hotspot-dev [mailto:hotspot-dev-bounces at openjdk.java.net] On
> Behalf Of Baesken, Matthias
> Sent: Montag, 30. April 2018 16:53
> To: 'hotspot-dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: [RFR] 8202427: Enhance os::print_memory_info on Windows
> 
> On Windows,
> the os::print_memory_info  misses a few  memory-related infos that might
> be interesting :
> - current and peak WorkingSet size  (= physical memory assigned to the
> process)
> - current and peak commit charge  (also known as "private bytes" in Windows
> tools)
> - on 32bit Windows :
> user-mode portion/free user mode portion  of virtual address-space
> (Total/AvailVirtual) because it shows how close do we get to the 2-4 GB per
> process border.
> 
> 
> - the current naming of "swap/free-swap" memory is a bit misleading;
> in the Windows world swap is a special page file used for UWP apps.
> (see Windows Internals :  "The swap file"  (chapter 5 Memory management)
> Windows 8 added another page file called a swap file. It is ... exclusively used
> for UWP (Universal Windows Platform) apps.
> Our output (ullTotalPageFile and ullAvailPageFile) is NOT about the UWP
> related values, it is about page file sizes
> (so calling it TotalPageFile/AvailPageFile in "Windows-speak" or just virtual
> memory might be more appropriate).
> 
> 
> https://msdn.microsoft.com/de-
> de/library/windows/desktop/aa366770(v=vs.85).aspx
> 
> documents it in the following way:
> ullTotalPageFile:
> The current committed memory limit for the system or the current process,
> whichever is smaller,...
> 
> ullAvailPageFile :
> The maximum amount of memory the current process can commit, in bytes.
> This value is equal to or smaller than the system-wide available commit value
> 
> 
> 
> Aditionally I suggest having output of the various memory-values  in M
> (megabyte) as well , the k  (kilobyte) output sometimes gives very high and
> unreadable numbers).
> 
> 
> Could you please  review my change ?
> 
> 
> Bug :
> 
> https://bugs.openjdk.java.net/browse/JDK-8202427
> 
> 
> Change :
> 
> http://cr.openjdk.java.net/~mbaesken/webrevs/8202427.0/
> 
> 
> Thanks, Matthias
>