On Thu, 2025-06-26 at 10:32 +0800, James Pang wrote: > thans for you suggestions, we have iowait from sar command too, copy here, > checking with infra team not found abnormal IO activities either. > 02:00:01 PM CPU %usr %nice %sys %iowait %irq %soft %steal > %guest %gnice %idle > 02:00:03 PM all 15.92 0.00 43.02 0.65 0.76 2.56 0.00 > 0.00 0.00 37.09
Crazy high system time. If it is not transparent hugepages, the other suspect is fork(). Turn on "log_connections" for a minute or two and see if there are lots of connections established. That can easily use your CPU. Other than that, I am out of guesses. > Frits Hoogland <frits.hoogl...@gmail.com> 於 2025年6月25日週三 下午10:27寫道： > > > On 25 Jun 2025, at 07:59, Laurenz Albe <laurenz.a...@cybertec.at> wrote: > > > > > > Run "sar -P all 1" and see if "%iowait" is high. > > > > I would (strongly) advise against the use of iowait as an indicator. I have heard that before, and I am sure you are right. I grant that if it is low, it may just mean that the CPU is under load. But if %iowait is high, my experience is that that indicates an I/O problem. Yours, Laurenz Albe
