memory profiling for C program

Question

Need to do a memory profiling of my C application ..

It should include footprint size and a RAM size ...

for example if my application is like below ..

#include <stdio.h>

int global = 10; /* initialized global variable */

int test_code(void)
{
    static int i = 100; /* Initialized static variable*/
    return 0;
}

Output:

[putta@linux]$ gcc memory-layout.c -c memory-layout 

[putta@linux]$ ls -ltrh  memory-layout.o
760 Nov  9 18:26 memory-layout

[putta@linux]$ size memory-layout.o
   text    data     bss     dec     hex filename
     67       8       0      75      4b memory-layout.o

So now which memory I should be considered for profiling footprint, and RAM when the program is loaded ..

is the below profiling is correct? footprint memory = 760 (which is sits flash or harddisk) RAM = 67+8+0 = 75 Bytes

Need suggestion from experts

Equatorial

As said below it is not a program. Whatever a running program can allocate memory (i.e. malloc) that would count into used memory (and of course not visible in the binary file). – Cranny

You'll have to define "memory footprint". Afaik, it means the total RAM usage, including: program code, static storage variables, stack usage and heap usage. – Scintilla

yes, since heap is depend on the real-time data I want to calculate without heap and stack .. so in my case I need to calculate like below RAM = program code, static and global variables, FLASH = Total memory required to store a program(resident memory) – Equatorial

I edited my answer to meet your question. – Raucous

Answer 1

Find the memory size of the object

If you want to know the size of your program on disk plus the size of text and data in RAM, on Linux/Unix you can use the size command:

$> size /bin/cat
text       data     bss     dec     hex filename
43422      1720    2472   47614    b9fe /bin/cat

The outputs of size are the memory sizes of different parts of the object file:

• text: (code segment) executable instructions
• data: (data segment) initialised global variables
• bss: (block started by symbols) statically-allocated variables

The last two columns, dec and hex, are respectively the sum of the other three (the overall size) in decimal and hexadecimal.

The size you are asking for is: the output of ls (that gives you the size on disk) plus the dec part of the output of the size command that gives you the size on RAM.

See also these posts: http://www.cyberciti.biz/faq/linux-find-size-of-text-data-segment-bss-uninitialized-data/, how to know the memory footprint of my binary executable

Find the memory footprint

When referring to a software application the footprint indicates the size of the memory consumed by the running process (runtime memory requirements).

Said that, it is clear that you should check the memory footprint when the process is running. I think (and other posts confirm it) that the only real option is to use a tool like valgrind.

Profile your application with valgrind

You can profile the memory using the Massif tool. Massif is an heap profiler but can also measure the size of the stack.

valgrind --tool=massif --stacks=yes

This will give you both the heap and stack memory usage. Then the information are stored in the file massif.out.???? that you can read with

ms_print massif.out.?????

The first output in the file is a nice chart of the memory usage during the running time.

--------------------------------------------------------------------------------
Command:            ./myprog -f d5.ini
Massif arguments:   --stacks=yes
ms_print arguments: massif.out.24377
--------------------------------------------------------------------------------


    MB
5.292^                                                    ##                  
     |    @                 :           :  @@   :      :  # ::::   :  :       
     |    @:::: ::    :   :@:@@::::::::::::@ :::::::::::::# ::::@::::@::::::::
     |    @:: ::: :::::::::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |    @:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |   @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     |   @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | ::@@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
     | : @@:: ::: : :::: ::@:@ ::: :: :::: @ :: ::: ::::::# ::::@: ::@::::::::
   0 +----------------------------------------------------------------------->Gi
     0                                                                   1.030

The details are stored in the file, inside different tables. To fully understand the output refers to the Valgrind manual page which seems really clear.

The option to trace the children is: --trace-children=yes

Interesting, it seems that there is no "actual memory usage of a process": https://unix.stackexchange.com/questions/164653/actual-memory-usage-of-a-process.

Raucous

I just need to calculate memory required to store the program in a disk and RAM required to load the program .. in my application heap and stack depends on the user realtime data , hence as of now I want to calculate only these things .. – Equatorial

actual size in bytes on disk (as you have done with ls) + dec (output of size) ..is it correct ? ls gets complete object file size (which includes all sections size) , so it should be 'actual size in bytes on disk only ls, is it right? – Equatorial

Yes I mean 'actual size on disk = ls' + 'size on RAM = dec'. I edited the text hope is more clear now. – Raucous

For better visualize output of valgrind there is a good GUI app massif visualizer. It can be install on debian-based systems with apt install massif-visualizer. Then run massif-visualizer massif.out.????? also see this – Coparcenary

Answer 2

This program is undefined: there is no main function.

A compiler reserves the right not to compile anything in this case, so resulting in a zero footprint and memory size.

Thirtieth

Actually I am making my features as a dynamic lib .. I do not need stack and heap memory as of now .. I just need to calculate the memory required to store the program in flash and memory required when I load my library in to RAM for execution .. – Equatorial

So why did you refer to your code as an 'application'? :-) – Thirtieth