How to determine maximum memory used by a program?

[Robert.Thompson]

Hello:

Is there a way to determine the maximum amount of memory that my program used during its' execution?

Thanks,

Rob.

[marcov]

You can get an idea using the values returned by this call:

https://www.freepascal.org/docs-html/rtl/system/getfpcheapstatus.html

The interpretation is a bit difficult though.

[Robert.Thompson]

Thank you.

[devEric69]

For information, if the cmem unit is somewhere in "uses" ( http://wiki.lazarus.freepascal.org/CMem ), then GetFPCHeapStatus returns 0 for all memory quantities (normal behaviour).

[Grahame Grieve]

ok, if it doesn't work with cmem, how can you find out how much memory is being used on the heap then?

[marcov]

If you use an external memory manager like cmem, you will need to make calls to that external memory manager for such stats. ((g)libc or msvcrt).

That is of course assuming that the memory manager has them at all.

Alternately you try to use operating system calls to get info about e.g. data segment size and the like.

[Grahame Grieve]

it's, umm, surprising that there's no facility in place like that for cmem. And there's no cross=platform way to find out how much the system has allocated to the program?

[KodeZwerg]

Maybe this helps on your journey about memory?

Code: Pascal  [Select][+][-]

1. program Project1;
2.  
3. uses
4.   Heaptrc
5.   {$IFDEF WINDOWS}
6.   , Windows
7.   {$ENDIF}
8.   ;
9.  
10. const
11.   CTestSize = DWORD(1024);
12.  
13. {$IFDEF WINDOWS}
14. type
15.   PPROCESS_MEMORY_COUNTERS = ^TProcessMemoryCounters;
16.   TProcessMemoryCounters = record
17.     cb: DWORD;
18.     PageFaultCount: DWORD;
19.     PeakWorkingSetSize: SIZE_T;
20.     WorkingSetSize: SIZE_T;
21.     QuotaPeakPagedPoolUsage: SIZE_T;
22.     QuotaPagedPoolUsage: SIZE_T;
23.     QuotaPeakNonPagedPoolUsage: SIZE_T;
24.     QuotaNonPagedPoolUsage: SIZE_T;
25.     PagefileUsage: SIZE_T;
26.     PeakPagefileUsage: SIZE_T;
27.   end;
28.  
29. function GetProcessMemoryInfo(hProcess: THandle; ppsmemCounters: PPROCESS_MEMORY_COUNTERS;
30.   cb: DWORD): BOOL; stdcall; external 'PsApi.dll' name 'GetProcessMemoryInfo';
31. {$ENDIF}
32.  
33. var
34.   LP: Pointer;
35.   LHeapStatus: THeapStatus;
36.   {$IFDEF WINDOWS}
37.   LProcessHandle: THandle;
38.   LProcessMemoryCounters: TProcessMemoryCounters;
39.   {$ENDIF}
40. begin
41.   // Allocate some memory to use
42.   GetMem(LP, CTestSize);
43.  
44.   // Get the current heap status
45.   LHeapStatus := GetHeapStatus;
46.  
47.   // Display the amount of used memory
48.   WriteLn('Used memory (Heap): ', LHeapStatus.TotalAddrSpace - LHeapStatus.TotalUncommitted);
49.  
50.   // Windows method
51.   {$IFDEF WINDOWS}
52.   // Get the process handle for the current process
53.   LProcessHandle := GetCurrentProcess;
54.  
55.   // Get the memory usage information for the process
56.   LProcessMemoryCounters.cb := SizeOf(LProcessMemoryCounters);
57.   if GetProcessMemoryInfo(LProcessHandle, @LProcessMemoryCounters, SizeOf(LProcessMemoryCounters)) then
58.   begin
59.     // Display the amount of used memory
60.     WriteLn('Used memory (Windows): ', LProcessMemoryCounters.WorkingSetSize);
61.   end;
62.   ReadLn;
63.   {$ENDIF}
64.  
65.   // Free the memory
66.   FreeMem(LP, CTestSize);
67. end.

[marcov]

it's, umm, surprising that there's no facility in place like that for cmem.

C never standardized that, so all various cmem backends differ.

And there's no cross=platform way to find out how much the system has allocated to the program?

No. Numbers often need interpretation(do shared or code area's count?  Really allocated vs allocated address space etc), and there is no commonality in the APIs. 

So it often depends on what you need it for, and how precise it needs to be.

[Grahame Grieve]

Wow. This is way harder than I expected it to be. What I want is something that seems super obvious to me: a number for how much memory is in use so I can log it. @KodeZwerg thanks for the windows code. For linux, it seems as though I read /proc/meminfo.

But that doesn't work for OSX. It seems like task_info is the thing I want, but I can't find a FPC translation for task_info.h. Is that because I'm looking in the wrong place or in the wrong way, or is it something that should be done? I'd do it, but I know nothing about header file translation on OSX

[Curt Carpenter]

Out of curiosity, why do you need to know (and how accurately)?   Would a Linux function like pmap be of use (if available in OSX?)

[Grahame Grieve]

I have a web server that runs on windows and monitor its memory usage, and cleans out caches when it starts running out of memory. it works on windows, but I'm trying to get off windows for stability purposes.

I can't get it to work on linux (intended server) or OSX (my dev), so that's what I'm trying to sort out.

pmap is cli application. How would that help me?

[marcov]

Note that your process size and running out of memory are two different things.

I don't know anything about OS X apis.

[Grahame Grieve]

I'm aware that they're different things, but they're somewhat interchangeable - something I can manage in config. But I can't get either.... I'm blind.

For now, I have removed cmem so I can get the internal heap size. It's not clear to me where I got the idea that cmem is a requirement on unix, but I did somewhere...

[KodeZwerg]

By reading I would suggest to not focus your app(s) or thread(s) memory usage, just have a look on available and free memory.
Sorry that I can again just show the Windows implementation that I am aware of:

Code: Pascal  [Select][+][-]

1. type
2.   _MEMORYSTATUSEX = record
3.     dwLength: DWORD;
4.     dwMemoryLoad: DWORD;
5.     ullTotalPhys: UInt64;
6.     ullAvailPhys: UInt64;
7.     ullTotalPageFile: UInt64;
8.     ullAvailPageFile: UInt64;
9.     ullTotalVirtual: UInt64;
10.     ullAvailVirtual: UInt64;
11.     ullAvailExtendedVirtual: UInt64;
12.   end;
13.   TMemoryStatusEx = _MEMORYSTATUSEX;
14.  
15. function GlobalMemoryStatusEx(var lpBuffer: TMemoryStatusEx): BOOL; stdcall; external kernel32;
16.  
17. var
18.   MemoryStatus: TMemoryStatusEx;
19. begin
20.   // Initialize the MEMORYSTATUSEX structure
21.   MemoryStatus.dwLength := SizeOf(MemoryStatus);
22.  
23.   // Get the memory status information
24.   if not GlobalMemoryStatusEx(MemoryStatus) then
25.     begin
26.       WriteLn('Error: ', SysErrorMessage(GetLastError));
27.       ReadLn;
28.       Exit;
29.     end;
30.  
31.   WriteLn('Total physical memory: ', MemoryStatus.ullTotalPhys div 1024, ' KB');
32.   WriteLn('Available physical memory: ', MemoryStatus.ullAvailPhys div 1024, ' KB');
33.   ReadLn;
34. end.

Anyway, that is just the physical memory, virtual memory is a total different story but same easy to measure.