[Valgrind-users] Large amount of instructions when profiling an empty program?

[Jon <jo...@po...>]

Hello,

I am entirely new to Valgrind and have just installed it on a Linux Mint 
system by running "apt-get install valgrind". To get started, I did run 
cachegrind on a very simple C program, which did nothing more than to 
add two integer variables. This is the result I got:

==12404== I   refs:      101,339
==12404== I1  misses:        711
==12404== LLi misses:        704
==12404== I1  miss rate:    0.70%
==12404== LLi miss rate:    0.69%
==12404==
==12404== D   refs:       38,424  (25,653 rd   + 12,771 wr)
==12404== D1  misses:      1,696  ( 1,210 rd   +    486 wr)
==12404== LLd misses:      1,502  ( 1,043 rd   +    459 wr)
==12404== D1  miss rate:     4.4% (   4.7%     +    3.8%  )
==12404== LLd miss rate:     3.9% (   4.0%     +    3.5%  )

I was surprised by the relatively large amount of instructions executed, 
so I did the following:

mint ~ $ cat test.c
int main() {
	return 0;
}

mint ~ $ gcc test.c -o test
mint ~ $ valgrind --tool=callgrind ./test
==12430== Callgrind, a call-graph generating cache profiler
==12430== Copyright (C) 2002-2013, and GNU GPL'd, by Josef Weidendorfer 
et al.
==12430== Using Valgrind-3.10.0.SVN and LibVEX; rerun with -h for 
copyright info
==12430== Command: ./test
==12430==
==12430== For interactive control, run 'callgrind_control -h'.
==12430==
==12430== Events    : Ir
==12430== Collected : 101336
==12430==
==12430== I   refs:      101,336

mint ~ $ callgrind_annotate callgrind.out.12430
--------------------------------------------------------------------------------
Profile data file 'callgrind.out.12430' (creator: callgrind-3.10.0.SVN)
--------------------------------------------------------------------------------
I1 cache:
D1 cache:
LL cache:
Timerange: Basic block 0 - 22401
Trigger: Program termination
Profiled target:  ./test (PID 12430, part 1)
Events recorded:  Ir
Events shown:     Ir
Event sort order: Ir
Thresholds:       99
Include dirs:
User annotated:
Auto-annotation:  off

--------------------------------------------------------------------------------
      Ir
--------------------------------------------------------------------------------
101,336  PROGRAM TOTALS

--------------------------------------------------------------------------------
     Ir  file:function
--------------------------------------------------------------------------------
21,478  /build/buildd/eglibc-2.19/elf/dl-lookup.c:do_lookup_x 
[/lib/x86_64-linux-gnu/ld-2.19.so]
17,844  /build/buildd/eglibc-2.19/elf/dl-lookup.c:_dl_lookup_symbol_x 
[/lib/x86_64-linux-gnu/ld-2.19.so]
16,283  
/build/buildd/eglibc-2.19/elf/../sysdeps/x86_64/dl-machine.h:_dl_relocate_object
  8,247  /build/buildd/eglibc-2.19/elf/do-rel.h:_dl_relocate_object
  8,231  
/build/buildd/eglibc-2.19/string/../sysdeps/x86_64/multiarch/../strcmp.S:strcmp'2 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  4,224  /build/buildd/eglibc-2.19/elf/dl-lookup.c:check_match.9458 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  2,226  
/build/buildd/eglibc-2.19/string/../sysdeps/x86_64/rtld-memset.S:memset 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,179  
/build/buildd/eglibc-2.19/elf/dl-version.c:_dl_check_map_versions 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,169  
/build/buildd/eglibc-2.19/string/../sysdeps/x86_64/multiarch/../strcmp.S:strcmp 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,147  /build/buildd/eglibc-2.19/elf/dl-load.c:_dl_map_object_from_fd 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,058  /build/buildd/eglibc-2.19/elf/dl-deps.c:_dl_map_object_deps 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,018  /build/buildd/eglibc-2.19/string/../string/memcmp.c:bcmp 
[/lib/x86_64-linux-gnu/ld-2.19.so]
  1,014  /build/buildd/eglibc-2.19/elf/dl-minimal.c:strsep 
[/lib/x86_64-linux-gnu/ld-2.19.so]
[...]


Since none of these functions were called by the program above, I wonder 
if this how the output is supposed to look. Were are these function 
calls coming from then? Or could there be something wrong with the way I 
installed Valgrind?

Best regards,
Jon