-h Print usage message.
-p PID Trace only this process.
-t TID Trace only this thread.
-c PPID Trace only child of this pid.
-i INTERVAL Print the summary at the specified interval (in seconds).
-d DURATION Total duration of trace (in seconds).
-T TOP Print only this many entries. Default: 10.
-x Trace only failed syscalls (i.e., the return value from the syscall was < 0).
-e ERRNO Trace only syscalls that failed with that error (e.g. -e EPERM or -e 1).
-m Display times in milliseconds. Default: microseconds.
-P Summarize by process and not by syscall.
-l List the syscalls recognized by the tool (hard-coded list). Syscalls beyond this list will still be displayed, as "[unknown: nnn]" where nnn is the syscall number.
--syscall SYSCALL Trace this syscall only (use option -l to get all recognized syscalls).
Summarize all syscalls by syscall: # syscount
Summarize all syscalls by process: # syscount -P
Summarize only failed syscalls: # syscount -x
Summarize only syscalls that failed with EPERM: # syscount -e EPERM
Trace PID 181 only: # syscount -p 181
Summarize syscalls counts and latencies: # syscount -L
PID Process ID
COMM Process name
SYSCALL Syscall name, or "[unknown: nnn]" for syscalls that aren't recognized
COUNT The number of events
TIME The total elapsed time (in us or ms)
Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.