We sometimes got memory leak problem, and we need to find the leaked memory, Here is a usful tool from MS, UMDH, it is included in WinDBG install package.
- It need the PDB files to analyse access the symbol table, then a human readable stack can be generated.
- You need to generated two set of current used memory, and compare the two to have a result.
- It compares the current used memory, so you can identify the still-in-use memory, That is the memory you stored somewhere, but they will actually never be used again, and should be released.
- And of cause, it can identify the memory with out a ptr pointing to when comparing.
You should let memory leak a little more to get a clear view of the result.
Here is the steps to use UMDH:
1. Install Windbg, you can get WinDBG from MS site:http://msdn.microsoft.com/en-us/windows/hardware/hh852365
2. Open a Dos Prompt as Administrator and navigate to the installation folder of WinDbg
3. Set Symbol Path as a System Variable
set _NT_SYMBOL_PATH= SRV*C:websymbols*http://msdl.microsoft.com/download/symbols; c:xosymbol
4. Download PDB file and copy to the “C:xosymbol” which is set part of above environment variable “_NT_SYMBOL_PATH”
5. Start collecting stack traces for user-mode allocations, run command:
gflags /i <Your_process_name.exe> +ust
6. Restart your process.
7. Keep it running, wait until it become steady..
8. Collect a baseline snapshot, run command:
umdh -pn:<Your_process_name.exe> -f:c:1.log
9. Wait until the memory usage of your process exceeds 1GB or more.
10. Generate a new snapshot, run command:
umdh -pn:<Your_process_name.exe> -f:c:2.log
11. Compare the two snapshots and get the final report from UMDH
umdh -d c:1.log c:2.log > c: esult12.log
12. In the result, we can see the stack where the leaked memory is allocated, You got a direct hint to resolve the leak problem.
And
if you need an example, please go to page https://www.hyzblog.com/use-umdh-identify-memory-leak-problem/