Show statistics of system calls
-c option can be used to summarize the statistics of every system call:
# strace -c ls
project
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
20.92 0.000050 50 1 munmap
19.25 0.000046 23 2 getdents64
14.64 0.000035 5 6 close
10.46 0.000025 25 1 write
10.46 0.000025 12 2 ioctl
9.21 0.000022 4 5 fstat
9.21 0.000022 7 3 brk
5.86 0.000014 3 4 openat
0.00 0.000000 0 5 read
0.00 0.000000 0 3 lseek
0.00 0.000000 0 12 mmap
0.00 0.000000 0 5 mprotect
0.00 0.000000 0 1 1 access
0.00 0.000000 0 1 execve
0.00 0.000000 0 2 1 arch_prctl
------ ----------- ----------- --------- --------- ----------------
100.00 0.000239 53 2 total
strace shows the time and error count of every system call. Similarly, -C option can print both regular output and statistics:
# strace -C ls
execve("/usr/bin/ls", ["ls"], 0x7ffe91857fa8 /* 21 vars */) = 0
brk(NULL) = 0x555bd69bc000
arch_prctl(0x3001 /* ARCH_??? */, 0x7ffc6ea19940) = -1 EINVAL (Invalid argument)
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=98317, ...}) = 0
mmap(NULL, 98317, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fdf81c6f000
......
close(1) = 0
close(2) = 0
exit_group(0) = ?
+++ exited with 0 +++
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
26.89 0.000256 21 12 mmap
13.97 0.000133 33 4 openat
11.45 0.000109 21 5 fstat
9.56 0.000091 15 6 close
7.98 0.000076 15 5 mprotect
......
Notice that -c and -C options are mutually exclusive. Please notice the time here measured is system time of every system call. If wall time is required, it is -w option :
# strace -w -c ls
project
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
19.85 0.000297 24 12 mmap
17.98 0.000270 269 1 execve
9.32 0.000140 23 6 close
......
There is another -S sortby option to customize histogram output sorted by calls, name and nothing (default is sorted by time). E.g.:
# strace -c -S calls ls
project
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
27.66 0.000164 13 12 mmap
8.26 0.000049 8 6 close
7.76 0.000046 9 5 read
5.40 0.000032 6 5 fstat
13.15 0.000078 15 5 mprotect
5.23 0.000031 7 4 openat
5.23 0.000031 10 3 lseek
4.05 0.000024 8 3 brk
4.05 0.000024 12 2 ioctl
1.69 0.000010 5 2 1 arch_prctl
7.93 0.000047 23 2 getdents64
4.55 0.000027 27 1 write
5.06 0.000030 30 1 munmap
0.00 0.000000 0 1 1 access
0.00 0.000000 0 1 execve
------ ----------- ----------- --------- --------- ----------------
100.00 0.000593 53 2 total