DTrace Topics One Liners
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[edit] DTrace Topics: One Liners
This is a list of DTrace One Liners, and is part of the DTrace Topics collection. See the DTrace Topics: Intro section for a general understanding of DTrace.
DTrace is a dynamic troubleshooting and analysis tool first introduced in the Solaris 10 and OpenSolaris operating systems.
Completion 
Difficulty 
Audience All DTrace users
[edit] Top One-Liners
The following are the top 10 one-liners to try out.
[edit] DTrace One Liners
This section is inteded as a concise list of one-liners. See the sections below for detailed explanations.
[edit] Processes
- New processes with arguments,
dtrace -n 'proc:::exec-success { trace(curpsinfo->pr_psargs); }'
[edit] Files
- Files opened by process name,
dtrace -n 'syscall::open*:entry { printf("%s %s",execname,copyinstr(arg0)); }'
- Files created using creat() by process name,
dtrace -n 'syscall::creat*:entry { printf("%s %s",execname,copyinstr(arg0)); }'
[edit] Syscalls
- Syscall count by process name,
dtrace -n 'syscall:::entry { @num[execname] = count(); }'
- Syscall count by syscall,
dtrace -n 'syscall:::entry { @num[probefunc] = count(); }'
- Syscall count by process ID,
dtrace -n 'syscall:::entry { @num[pid,execname] = count(); }'
- Read bytes by process name,
dtrace -n 'sysinfo:::readch { @bytes[execname] = sum(arg0); }'
[edit] I/O
- Write bytes by process name,
dtrace -n 'sysinfo:::writech { @bytes[execname] = sum(arg0); }'
- Read size distribution by process name,
dtrace -n 'sysinfo:::readch { @dist[execname] = quantize(arg0); }'
- Write size distribution by process name,
dtrace -n 'sysinfo:::writech { @dist[execname] = quantize(arg0); }'
[edit] Physical I/O
- Disk size by process ID,
dtrace -n 'io:::start { printf("%d %s %d",pid,execname,args[0]->b_bcount); }'
- Disk size aggregation
dtrace -n 'io:::start { @size[execname] = quantize(args[0]->b_bcount); }'
- Pages paged in by process name,
dtrace -n 'vminfo:::pgpgin { @pg[execname] = sum(arg0); }'
[edit] Memory
- Minor faults by process name,
dtrace -n 'vminfo:::as_fault { @mem[execname] = sum(arg0); }'
[edit] User-land
- Sample user stack trace of specified process ID at 1001 Hertz
dtrace -n 'profile-1001 /pid == $target/ { @num[ustack()] = count(); }' -p PID
- Trace why threads are context switching off the CPU, from the user-land perspective,
dtrace -n 'sched:::off-cpu { @[execname, ustack()] = count(); }'
- User stack size for processes
dtrace -n 'sched:::on-cpu { @[execname] = max(curthread->t_procp->p_stksize);}'
[edit] Kernel
- Sample kernel stack trace at 1001 Hertz
dtrace -n 'profile-1001 /!pid/ { @num[stack()] = count(); }'
- Interrupts by CPU,
dtrace -n 'sdt:::interrupt-start { @num[cpu] = count(); }'
- CPU cross calls by process name,
dtrace -n 'sysinfo:::xcalls { @num[execname] = count(); }'
- Trace why threads are context switching off the CPU, from the kernel perspective,
dtrace -n 'sched:::off-cpu { @[execname, stack()] = count(); }'
- Kernel funtion calls by module
dtrace -n 'fbt:::entry { @calls[probemod] = count(); }'
[edit] Locks
- Trace user-level lock statistics for 10 seconds, with 8 line stack traces (uses DTrace),
plockstat -s8 -e10 -p PID
- Trace kernel lock statistics for 10 seconds, with 8 line stack traces (uses DTrace),
lockstat -s8 sleep 10
- Lock time by process name,
dtrace -n 'lockstat:::adaptive-block { @time[execname] = sum(arg1); }'
- Lock distribution by process name,
dtrace -n 'lockstat:::adaptive-block { @time[execname] = quantize(arg1); }'
[edit] Zones
- Syscalls by zonename
dtrace -n 'syscall:::entry { @num[zonename] = count(); }'
[edit] DTrace Longer One Liners
- New processes with arguments and time,
dtrace -qn 'syscall::exec*:return { printf("%Y %s\n",walltimestamp,curpsinfo->pr_psargs); }'
- Successful signal details,
dtrace -n 'proc:::signal-send /pid/ { printf("%s -%d %d",execname,args[2],args[1]->pr_pid); }'
[edit] References
Most of these onliners are in the DTraceToolkit as docs/oneliners.txt, and as Appendix B in Solaris Performance and Tools.
