(gdb) print 100
$7 = 100
(gdb) print/x 100
$8 = 0x64
(gdb) print/o 100
$9 = 0144
(gdb) print/t 100
$10 = 1100100
(gdb) p p
$11 = (person_t) 0x5555557572a0
(gdb) p (char*)p.name
$12 = 0x5555557572c0 "Alice"

(gdb) b main.c:89 if *name == 'A'
Breakpoint 8 at 0x555555554aca: file main.c, line 89.

(gdb) bt
#0  print_persons (p=0x555555757260) at main.c:78
#1  0x0000555555554b5a in main (argc=1, argv=0x7fffffffd698) at main.c:98

$ valgrind --leak-check=full <program>
==17417== Memcheck, a memory error detector
==17417== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==17417== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==17417== Command: ./main
==17417== 
==17417== 
==17417== HEAP SUMMARY:
==17417==     in use at exit: 2,048 bytes in 2 blocks
==17417==   total heap usage: 2 allocs, 0 frees, 2,048 bytes allocated
==17417== 
==17417== 1,024 bytes in 1 blocks are definitely lost in loss record 1 of 2
==17417==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==17417==    by 0x10865B: f (main.c:6)
==17417==    by 0x108689: main (main.c:20)
==17417== 
==17417== 1,024 bytes in 1 blocks are definitely lost in loss record 2 of 2
==17417==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==17417==    by 0x108674: g (main.c:13)
==17417==    by 0x108693: main (main.c:21)
==17417== 
==17417== LEAK SUMMARY:
==17417==    definitely lost: 2,048 bytes in 2 blocks
==17417==    indirectly lost: 0 bytes in 0 blocks
==17417==      possibly lost: 0 bytes in 0 blocks
==17417==    still reachable: 0 bytes in 0 blocks
==17417==         suppressed: 0 bytes in 0 blocks
==17417== 
==17417== For counts of detected and suppressed errors, rerun with: -v
==17417== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)

$ valgrind --tool=helgrind ./main

略

==18542== This conflicts with a previous write of size 4 by thread #2
==18542== Locks held: none
==18542==    at 0x10874B: f (main.c:8)
==18542==    by 0x4C36C26: ??? (in /usr/lib/valgrind/vgpreload_helgrind-amd64-linux.so)
==18542==    by 0x4E496DA: start_thread (pthread_create.c:463)
==18542==    by 0x518288E: clone (clone.S:95)
==18542==  Address 0x309014 is 0 bytes inside data symbol "var"

略

% time sleep 3  
sleep 3  0.00s user 0.00s system 0% cpu 3.003 total

$ gprof main gmon.out
Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  us/call  us/call  name    
 51.65      0.56     0.56     1000   562.99   562.99  g
 48.88      1.10     0.53     1000   532.83   532.83  f

(以下略)

% sudo perf record -a -g -F 997 sleep 10
[ perf record: Woken up 11 times to write data ]
[ perf record: Captured and wrote 6.181 MB perf.data (20127 samples) ]
% sudo perf report --stdio 
# Total Lost Samples: 0
#
# Samples: 20K of event 'cycles:ppp'
# Event count (approx.): 14794093886
#
# Children      Self  Command          Shared Object                    Symbol                                                                                                                             
# ........  ........  ............... ...............................................................
#
    37.91%     0.00%  swapper          [kernel.kallsyms]                [k] secondary_startup_64
            |
            ---secondary_startup_64
               |          
               |--33.30%--start_secondary
               |          cpu_startup_entry

Samples: 55K of event 'cycles:ppp', Event count (approx.): 10091157696
Overhead  Shared Object                           Symbol
   3.20%  [kernel]                                [k] dw_readl
   1.61%  chrome                                  [.] 0x0000000004e67400
   1.56%  chrome                                  [.] 0x00000000033b0b83
   1.50%  chrome                                  [.] _fini
   1.33%  [kernel]                                [k] module_get_kallsym
   1.29%  [kernel]                                [k] syscall_return_via_sysret
   0.97%  libpthread-2.27.so                      [.] __pthread_mutex_lock
   0.83%  perf                                    [.] 0x00000000001f78a0