thread_group_start_cputime(9)

🎀 NAME 🎀

okay bestie, welcome to the Kernel API Manual corner for thread_group_start_cputime — aka the function that starts cputime and returns a sample. periodt. ✨

✨ SYNOPSIS ✨

void thread_group_start_cputime (struct task_struct *tsk , u64 *samples
);

💖 ARGUMENTS 💖

• tsk — the task for which cputime needs to be started. 🫶
• samples — storage for time samples. 🎀

🧚 DESCRIPTION 🧚

okay so here’s the tea ☕: the thread group cputime accounting is avoided when there are no posix CPU timers armed. no timers armed, no accounting, iykyk. 💅

Before starting a timer, it’s required to check whether the time accounting is active. If it’s not active, a full update of the atomic accounting store needs to be done, and the accounting enabled. literally required, bestie. 🔥

Then it updates the times with an uptodate sample of the thread group cputimes. slay. ✨

🔥 SEE ALSO 🔥

• Kernel file ./kernel/time/posix-cpu-timers.c 🦋
• thread_group_sample_cputime(9), task_cputimers_expired(9), fastpath_timer_check(9) — the whole friend group. 💜

💖 sign-off time, bestie: from the Kernel API Manual, source ./kernel/time, dated October 2026, page thread_group_start_cputime(9). go read the kernel source, it’s giving main character energy 🫶✨