First call to omrsysinfo_get_memory_info on Windows can be very slow

[JamesKingdon]

On Windows omrsysinfo_get_memory_info is implemented with the PDH apis. The first time these are used incurs a significant penalty. Specifically the first call to PdhAddCounter at

omr/port/win32/omrsysinfo.c

Line 932 in d2c8425

status = PdhAddCounter(statsHandle,

has been seen to take over 2s, with subsequent calls taking only a few microseconds.

While 2 to 3 seconds may not seem much it can be noticeable to an interactive user and significant for short lived JVMs. I have not yet found out why it can take much longer on some machines than others. It might be worth exploring if there are alternatives for getting the required memory stats.