procscope

Stream per-process CPU time, memory, thread, fault, and energy counters on macOS.

procscope continuously prints process snapshots by default. Use --count 1 to emit a single sample and exit.

cumulative CPU time split into total, user, and system time
resident and virtual memory sizes, in bytes by default
thread counts, page faults, page-ins, and context switches
cumulative process energy consumed

It uses proc_pidinfo(PROC_PIDTASKINFO) for CPU and memory, and proc_pid_rusage(RUSAGE_INFO_V6) for energy counters.

Example

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./zig-out/bin/procscope --count 1 12345
./zig-out/bin/procscope --human --count 5 12345
./zig-out/bin/procscope --interval 1 --count 5 12345

Process ID: 12345
Command Line: /usr/bin/python3 script.py --port 8080
CPU(s)     USER(s)    SYS(s)     RSS(bytes)    VIRT(bytes)   TH       FAULTS     PAGEINS   CSW        ENERGY(mJ)
18.764     15.932     2.832      103809024     1930428416    4/12     4248       19        10668      511.200
18.781     15.947     2.834      103809024     1930428416    4/12     4250       19        10692      511.742

Process ID: 12345
Command Line: /usr/bin/python3 script.py --port 8080
CPU(s)     USER(s)    SYS(s)     RSS           VIRT          TH       FAULTS     PAGEINS   CSW        ENERGY(mJ)
18.764     15.932     2.832      99.0MiB       1.8GiB        4/12     4248       19        10668      511.200

Key flags

Flag	Description
`-H, --human`	Format memory sizes with adaptive units
`-i, --interval`	Delay in seconds between successive samples
`-n, --count`	Number of samples to print, `0` means infinite

Metric meanings

Command Line: argv reconstructed from KERN_PROCARGS2 when available; otherwise the executable path is shown.
CPU(s): cumulative CPU time charged to the process since it started.
USER(s): cumulative user-space CPU time charged to the process since it started.
SYS(s): cumulative kernel-space CPU time charged to the process since it started.
RSS: physical memory currently resident for this process; --human switches to adaptive units.
VIRT: total virtual address space reserved by this process; --human switches to adaptive units.
TH: runnable threads versus all task threads, formatted as running/total.
FAULTS: cumulative page faults since the process started.
PAGEINS: cumulative page-ins serviced from storage since the process started.
CSW: cumulative task context switches since the process started.
ENERGY(mJ): cumulative process energy counter from ri_energy_nj, shown in millijoules.

Last modified July 19, 2026: feat(procscope): add macOS process monitor (#86) (8edd28e)