Collect and sum statistics of `strace` commands?

I know that I can runstrace -c ls to collect system call statistics on the ls executable. However, I want to run the command strace -c {some executable here} mulitiple times over different executables, merge the individual results, and then write to a single file.

I want to merge the ‘syscall’ and the ‘calls’ columns. So for example, if ls makes 19 mmap system calls and tr makes 11 mmap system calls, I would like to merge those results so that the final statistics simply show 30 mmap system calls overall in some file. Moreover, if a system call only appears in one executable, it should still be included in the final results.

How can I do that?

Answer

Using grep to find mmap calls, which are then piped to datamash (on Debian variants, install withapt install datamash) to group by column 5, (i.e. mmap), and sum column 4:

for f in /bin/ls /bin/tr ; do strace -c $f 2>&1 ; done |  
    grep mmap | datamash -W -g5 sum 4

Output:

mmap    29

---

1. Example showing what similar data looked like before it was summed:

   for f in /bin/false /bin/true ; do strace -c $f 2>&1 ; done |  
        grep mmap | tee /tmp/old | datamash -W -g5 sum 4 ; echo --- ; cat /tmp/old
   
   mmap    12
   ---
     0.00    0.000000           0         6           mmap
     0.00    0.000000           0         6           mmap
   

2. The -s switch lets datamash group, sort, and separately sum all the syscalls:

   for f in /bin/pwd  /bin/false /bin/true ; do
        strace -c $f 2>&1 > /dev/null |
            grep -v ':' | cut --complement -c 42-50 |
            sed '1s/^% /%_/;2d' | head -n -2 ;  
   done | sed -n '1p;/^%/d;p' | datamash -HW -sg5 sum 4  | 
          xargs printf "%-12st%14sn"
   

   (Note that the strace output needs cleaning, which is done by cut, sed, et al…)

   Output:

   GroupBy(syscall)        sum(calls)
   access                       9
   arch_prctl                   3
   brk                          5
   close                       23
   execve                       3
   fstat                       22
   getcwd                       1
   ioctl                        1
   mmap                        31
   mprotect                    12
   munmap                       3
   open                        34
   read                         5
   write                        1