RFR: JDK-8301661: Enhance os::pd_print_cpu_info on macOS and Windows

[David Holmes]

On Fri, 3 Feb 2023 08:25:09 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> Enhance os::pd_print_cpu_info on macOS and Windows by information about CPU frequency and caches.
> On Windows , this info can be obtained by the Processor Power Information API or "powerbase" (CallNtPowerInformation , see https://learn.microsoft.com/en-us/windows/win32/api/powerbase/nf-powerbase-callntpowerinformation ); this is available since Windows Server 2003/XP.
> On macOS, sysctlbyname can be used.

src/hotspot/os/windows/os_windows.cpp line 94:

> 92: 
> 93: #include <malloc.h>
> 94: #include <powrprof.h>

The header should be `powerbase.h`

src/hotspot/os/windows/os_windows.cpp line 1888:

> 1886:     ULONG MaxIdleState;
> 1887:     ULONG CurrentIdleState;
> 1888: } PROCESSOR_POWER_INFORMATION, *PTR_PROCESSOR_POWER_INFORMATION;

We don't need the `*PTR_PROCESSOR_POWER_INFORMATION`

src/hotspot/os/windows/os_windows.cpp line 1891:

> 1889: 
> 1890: // additional lib needed for PowerProf functionality
> 1891: #pragma comment(lib, "Powrprof.lib")

Not sure about this mechanism versus adding it to Makefile ??

src/hotspot/os/windows/os_windows.cpp line 1898:

> 1896: 
> 1897:   PROCESSOR_POWER_INFORMATION ppi;
> 1898:   size_t sz_check = sizeof(ppi) * (size_t)si.dwNumberOfProcessors;

We already have `dwNumberOfProcessors` available in `processor_count()` - though we may have to zero-initialize it and check for zero in case we crash before we've done os::init

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PR: https://git.openjdk.org/jdk/pull/12403