Taken from
Using strace as a troubleshooting tool (linuxcluster.wordpress.com) Strace, when runs in conjunction with a program do output all the calls made to the kernel by the program.
One of quick way to found out what is going on in your program is to do
$ strace -c ./my_hello_world_program
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
74.80 0.002998 1499 2 wait4
21.91 0.000878 4 221 read
0.95 0.000038 0 237 2 mmap
0.77 0.000031 10 3 1 mkdir
0.67 0.000027 0 566 361 open
0.35 0.000014 0 81 mprotect
0.30 0.000012 0 62 37 stat
0.25 0.000010 0 225 close
0.00 0.000000 0 37 1 write
0.00 0.000000 0 132 fstat
0.00 0.000000 0 8 poll
0.00 0.000000 0 2 lseek
0.00 0.000000 0 120 munmap
0.00 0.000000 0 15 brk
0.00 0.000000 0 16 rt_sigaction
................
................
------ ----------- ----------- --------- --------- ----------------
100.00 0.004008 1990 411 total
If you wish to do a tracing, just do a, you can easily find out the error if there was....
$ strace ./my_hello_world_program
............
............
open("/tmp/openmpi-sessions-root@starfruit-h00.cluster.spms.ntu.edu.sg_0/25979/1/0",
O_RDONLY|O_NONBLOCK|O_DIRECTORY) = -1 ENOENT (No such file or directory)
munmap(0x2b46e05ef000, 2111200) = 0
munmap(0x2b46dffe5000, 2102312) = 0
munmap(0x2b46dfdde000, 2123264) = 0
munmap(0x2b46e103f000, 2106960) = 0
munmap(0x2b46e1242000, 2104560) = 0
munmap(0x2b46e269d000, 2114912) = 0
munmap(0x2b46e41c9000, 2145008) = 0
munmap(0x2b46e43d5000, 2162608) = 0
If you wish the output of strace to a file instead, do use the argument -o
$ strace -o strace_output_file ./my_hello_world_program
If you wish to trace system call, process,network, you can use the "-e trace=file", "-e trace=process", "-e trace=network",
$ strace -e trace=open,close,read,write ./my_hello_w0rld_program
$ strace -e trace=stat,chmod,unlink ./my_hello_world_program
Further Information:
- Solutions for tracing UNIX applications (IBM DeveloperWorks)
- strace - A very powerful troubleshooting tool for all Linux users (linuxhelp.blogspot.com)
- Ten commands every linux developer should know (Linux Journal)
