On Tue, 17 Sep 2024 14:26:00 GMT, Simon Tooke <sto...@openjdk.org> wrote:
>>> Sorry if I'm holding this up. The reasoning did get confusing to me. >>> >>> We are not always good at documenting these commands. But at some point, >>> somebody among us will hopefully document them, or explain it to somebody >>> who will. There will need to be explanation of how the outputs differ on >>> Linux and Windows, and how the information can be used. >>> >>> RSS is on Linux only... No problem, that has a well-understood meaning on >>> *nix systems. >>> >>> offset? It's the same as the size of the previous line of output. Or the >>> sum of sizes if there are multiple lines as part of the same allocation. >>> It's Windows only. It's not likely this is more useful on Windows than >>> Linux. Is it considered missing on Linux, or just not needed? >> >> A general note, this is an OS-specific tool. There will be overlapping >> between OSes, but it is understood that the analyst knows the idiosyncrasies >> of the target OS' memory management. We should not try to generalize, and we >> should use OS specific terms. >> >> So, RSS makes sense in Linux. On Windows, a roughly corresponding term would >> be WorkingSetSize, but we don't get on a per-mapping base. >> >> What Simon prints as "offset" is the distance to the allocation base, aka >> the start of the memory region allocated with VirtualAlloc. It's a two-layer >> system, with the kernel keeping track of both committed/uncommitted regions >> as well as the underlying allocations. That concept does not exist on Linux >> at the kernel level. >> >> Offset is good to know since one can see where an allocation started (offset >> 0). I would add a short text in the legend, since it is easily confused with >> file offset for file mappings. > > @tstuefe I have updated the legend, thanks for the note. @stooke this is causing a build failure in our CI with a slowdebug build: [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(126): error C2504: 'os::win32': base class undefined [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(130): error C2027: use of undefined type 'os::win32' [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\share\runtime/os.hpp(1015): note: see declaration of 'os::win32' [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(130): error C3861: 'print_windows_version': identifier not found [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(131): error C2027: use of undefined type 'os::win32' [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\share\runtime/os.hpp(1015): note: see declaration of 'os::win32' [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(131): error C3861: 'print_uptime_info': identifier not found [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(132): error C2653: 'VM_Version': is not a class or namespace name [2024-09-18T11:35:44,152Z] c:\sb\prod\1726658372\workspace\open\src\hotspot\os\windows\memMapPrinter_windows.cpp(132): error C3861: 'print_platform_virtualization_info': identifier not found I can't file a bug at present but please attend to this ASAP. ------------- PR Comment: https://git.openjdk.org/jdk/pull/20597#issuecomment-2358243307
