proc_pid_timers(5)

✨ proc_pid_timers — the manual page bestie 💖

ok so this is /proc_pid_timers(5), a File Formats Manual situation, and it's genuinely such a fun little corner of procfs. let's get into it 🫶

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💫 NAME

/proc/pid/timers — POSIX timers, bestie. that's the whole vibe.

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🌸 DESCRIPTION

/proc/pid/timers</p> (since Linux 3.10) 🎀

this file is literally a lil list of every POSIX timer this process has going on. each timer shows up as a group of lines, and each group kicks off with a line that starts with the string ID:. here's what that looks like:

ID: 1
signal: 60/00007fff86e452a8
notify: signal/pid.2634
ClockID: 0
ID: 0
signal: 60/00007fff86e452a8
notify: signal/pid.2634
ClockID: 1

now let's break down what each of those lines is actually telling you, because they are lowkey doing a lot 😭

• ID — the ID for this timer. and no, before you ask, this is not the same as the timer ID that timer_create(2) hands back to you. it's actually the same kernel-internal ID that you can get your hands on via the si_timerid field of the siginfo_t structure (go peek at sigaction(2) for that one 👀).
• signal — this is the signal number that this timer uses to deliver notifications, followed by a slash, and then the sigev_value value that got supplied to the signal handler. heads up tho: this is valid only for timers that notify via a signal. no signal, no dice.
• notify — okay so the part before the slash tells you the mechanism this timer uses to deliver notifications, and it's one of "thread", "signal", or "none". right after the slash you get either the string "tid" for timers with SIGEV_THREAD_ID notification, or "pid" for timers that notify by other mechanisms. and then, following the ".", is the PID of the process (or the kernel thread ID of the thread) that's gonna get a signal delivered to it if the timer delivers notifications via a signal. so much info in one lil line fr fr 💅
• ClockID — this field IDs the clock that the timer uses for measuring time. for most clocks this is just a number that matches one of the user-space CLOCK_* constants exposed via <time.h>. but ✨ the special girlies ✨ are: CLOCK_PROCESS_CPUTIME_ID timers, which display with a value of -6 in this field, and CLOCK_THREAD_CPUTIME_ID timers, which display with a value of -2. iconic, honestly.

🚨 important note bestie: this file is available only when the kernel was configured with CONFIG_CHECKPOINT_RESTORE. no config, no timers file. that's the rule 🫠

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🦋 SEE ALSO

• proc(5)

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and that's the tea, babe 💜 slay, you now fully understand /proc/pid/timers. go forth and read your timers.

— with love from Linux man-pages 6.20, dated 2026-02-08 🎀✨👑