如何测量给定时刻的进程内存使用情况

Question

Here is the way to measure peak memory usage of current process since the start of the process.

process= psutil.Process(os.getpid())
process.memory_full_info().peak_wset

But what if I want to do few measurements for different parts(functions) of the program? How can I get memory used by program in any desired moment to check difference before and after? Maybe there is the way to reset peak_wset?

Answer 1

Currently you no longer need os.getpid() when inspecting current process. Just use psutil.Process()

1) To measure if the peak memory increased or not (never decreased) before a function call, invoke this before and after a function call and take the difference:

• On Windows:
  • psutil.Process().memory_info().peak_wset
  • psutil.Process().memory_full_info().peak_wset
• On Linux:
  • I read here the resource.getrusage(resource.RUSAGE_SELF).ru_maxrss would do the trick but I haven't tested.

2) To measure the current memory variation before and after a function call, invoke it before and after a function call and take the difference:

• On Windows and Linux:
  • psutil.Process().memory_info().rss
  • psutil.Process().memory_full_info().rss
  • psutil.Process().memory_full_info().uss

From docs :

memory_full_info() returns the same information as memory_info() , plus, on some platform (Linux, macOS, Windows), also provides additional metrics (USS, PSS and swap). The additional metrics provide a better representation of “effective” process memory consumption (in case of USS) as explained in detail in this blog post. It does so by passing through the whole process address. As such it usually requires higher user privileges than memory_info() and is considerably slower. On platforms where extra fields are not implemented this simply returns the same metrics as memory_info() .

uss (Linux, macOS, Windows): aka “Unique Set Size”, this is the memory which is unique to a process and which would be freed if the process was terminated right now.

Note : uss is probably the most representative metric for determining how much memory is actually being used by a process.

3) To measure the specific memory a function call used during its execution, before any garbage collection takes place, you need a memory profiler .