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
abnormalIO 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.hoogland@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.albe@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
