Full reproducer referenced in the kernel revert:
#include <sys/epoll.h>
#include <sys/time.h>
#include <sys/wait.h>
int main() {
int e = epoll_create1(0);
struct epoll_event event = {.events = EPOLLIN};
epoll_ctl(e, EPOLL_CTL_ADD, 0, &event);
const struct timespec timeout = {.tv_nsec = 1};
epoll_pwait2(e, &event, 1, &timeout, 0);
}
I tested this locally and it really spins on 6.14.0.17-17 while behaving
normally on 6.14.0.15-15.
I'm marking the snapd and go tasks as invalid
** Changed in: golang
Status: New => Invalid
** Changed in: snapd
Importance: High => Undecided
** Changed in: snapd
Status: Confirmed => Invalid
** Changed in: snapd
Assignee: Zygmunt Krynicki (zyga) => (unassigned)
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https://bugs.launchpad.net/bugs/2110289
Title:
snapd has high CPU usage for exactly 150 seconds every 5, 7.5 or 10
minutes
Status in Go:
Invalid
Status in Linux:
Fix Committed
Status in snapd:
Invalid
Status in linux package in Ubuntu:
Confirmed
Bug description:
Since recently, I have observed a periodic high CPU spike on the snapd
process.
It first occurs 5 minutes after start of the snapd systemd service. It
always lasts for exactly 150 seconds (2.5 minutes) and occurs every 5,
7.5 or 10 minutes. It maxes out a CPU core for the 150 seconds it is
running.
If you run `sudo snap refresh` while the CPU spike is occurring, the
spike stops immediately.
I have attached a CPU usage log which logs the CPU usage of the snapd
process every 5 seconds.
Some info about my system:
snap --version:
snap 2.68.4
snapd 2.68.4
series 16
ubuntu 22.04
kernel 6.14.5-1-liquorix-amd64
lsb_release -a:
Distributor ID: Ubuntu
Description: Ubuntu 22.04.5 LTS
Release: 22.04
Codename: jammy
uname -a:
Linux schneeflocke 6.14.5-1-liquorix-amd64 #1 ZEN SMP PREEMPT_DYNAMIC
liquorix 6.14-7ubuntu1~jammy (2025-05 x86_64 x86_64 x86_64 GNU/Linux
Measurements:
Spike Start - Spike End -> Total Time
12:25:26 - 12:22:56 -> 2:30 min
12:35:26 - 12:37:56 -> 2:30 min
12:40:26 - 12:42:56 -> 2:30 min
12:47:56 - 12:50:26 -> 2:30 min
12:52:56 - 12:55:26 -> 2:30 min
What additional info can I provide to identify the problem?
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