MacOS Process Monitoring

Processes on MacOS can be easily monitored using the DTrace facility.

Rather than using the DTrace facility directly, it is easier to use one of the precompiled DTrace applications that Apple ships with MacOS.

You can find the list of applications with the "man -k trace" command:

$ man -k dtrace
bitesize.d(1m)           - analyse disk I/O size by process. Uses DTrace
cpuwalk.d(1m)            - Measure which CPUs a process runs on. Uses DTrace
creatbyproc.d(1m)        - snoop creat()s by process name. Uses DTrace
dappprof(1m)             - profile user and lib function usage. Uses DTrace
dapptrace(1m)            - trace user and library function usage. Uses DTrace
diskhits(1m)             - disk access by file offset. Uses DTrace
dispqlen.d(1m)           - dispatcher queue length by CPU. Uses DTrace
dtrace(1)                - generic front-end to the DTrace facility
dtruss(1m)               - process syscall details. Uses DTrace
errinfo(1m)              - print errno for syscall fails. Uses DTrace
execsnoop(1m)            - snoop new process execution. Uses DTrace
fddist(1m)               - file descriptor usage distributions. Uses DTrace
filebyproc.d(1m)         - snoop opens by process name. Uses DTrace
hotspot.d(1m)            - print disk event by location. Uses DTrace
httpdstat.d(1m)          - realtime httpd statistics. Uses DTrace
iofile.d(1m)             - I/O wait time by file and process. Uses DTrace
iofileb.d(1m)            - I/O bytes by file and process. Uses DTrace
iopattern(1m)            - print disk I/O pattern. Uses DTrace
iopending(1m)            - plot number of pending disk events. Uses DTrace
iosnoop(1m)              - snoop I/O events as they occur. Uses DTrace
iotop(1m)                - display top disk I/O events by process. Uses DTrace
kill.d(1m)               - snoop process signals as they occur. Uses DTrace
lastwords(1m)            - print syscalls before exit. Uses DTrace
loads.d(1m)              - print load averages. Uses DTrace
newproc.d(1m)            - snoop new processes. Uses DTrace
opensnoop(1m)            - snoop file opens as they occur. Uses DTrace
pathopens.d(1m)          - full pathnames opened ok count. Uses DTrace
pidpersec.d(1m)          - print new PIDs per sec. Uses DTrace
plockstat(1)             - front-end to DTrace to print statistics about POSIX mutexes and read/write locks
priclass.d(1m)           - priority distribution by scheduling class. Uses DTrace
pridist.d(1m)            - process priority distribution. Uses DTrace
procsystime(1m)          - analyse system call times. Uses DTrace
runocc.d(1m)             - run queue occupancy by CPU. Uses DTrace
rwbypid.d(1m)            - read/write calls by PID. Uses DTrace
rwbytype.d(1m)           - read/write bytes by vnode type. Uses DTrace
rwsnoop(1m)              - snoop read/write events. Uses DTrace
sampleproc(1m)           - sample processes on the CPUs. Uses DTrace
seeksize.d(1m)           - print disk event seek report. Uses DTrace
setuids.d(1m)            - snoop setuid calls as they occur. Uses DTrace
sigdist.d(1m)            - signal distribution by process. Uses DTrace
syscallbypid.d(1m)       - syscalls by process ID. Uses DTrace
syscallbyproc.d(1m)      - syscalls by process name. Uses DTrace
syscallbysysc.d(1m)      - syscalls by syscall. Uses DTrace
topsyscall(1m)           - top syscalls by syscall name. Uses DTrace
topsysproc(1m)           - top syscalls by process name. Uses DTrace
weblatency.d(1m)         - website latency statistics. Uses DTrace
<pre>

For example, to monitor all file opens, use:

<pre>
$ sudo filebyproc.d
dtrace: script '/usr/bin/filebyproc.d' matched 3 probes
CPU     ID                    FUNCTION:NAME
  1  18510                       open:entry mds /private/var/db/sudo/simsong
  1  18510                       open:entry mds /private/var/db/sudo/simsong
  0  18510                       open:entry mds .
dtrace: error on enabled probe ID 1 (ID 19296: syscall::open_nocancel:entry): invalid address (0x7fff5fc2dc7f) in action #2 at DIF offset 24
  0  18510                       open:entry backupd-helper /dev/dtracehelper
  0  18510                       open:entry launchd /var/run
  1  19296              open_nocancel:entry backupd-helper /dev/urandom
  1  19296              open_nocancel:entry backupd-helper /dev/urandom
  1  19296              open_nocancel:entry backupd-helper /System/Library/CoreServices/backupd.bundle/Contents/Resources
  1  18510                       open:entry backupd-helper /System/Library/CoreServices/backupd.bundle/Contents/Resources/Resources/Info-macos.plist
  1  18510                       open:entry backupd-helper /System/Library/CoreServices/backupd.bundle/Contents/Resources/Resources/Info.plist
  1  18510                       open:entry backupd-helper /System/Library/CoreServices/backupd.bundle/Contents/Resources/backupd-helper
  1  19296              open_nocancel:entry backupd-helper /etc/sysinfo.conf
  1  18510                       open:entry backupd-helper /var/root/Library/Preferences/ByHost/.GlobalPreferences.A59F3B73-8D3E-5DC8-B7F7-DBD934505101.plist
  1  18510                       open:entry backupd-helper /var/root/Library/Preferences/.GlobalPreferences.plist
  1  18510                       open:entry backupd-helper /Library/Preferences/com.apple.TimeMachine.plist
  1  18510                       open:entry backupd-helper /Library/Preferences/.GlobalPreferences.plist
  1  19296              open_nocancel:entry backupd-helper /var/run/.autoBackup
  1  18510                       open:entry backupd-helper /private/var/db/.TimeMachine.Results.plist