Re: Help understanding slow down

Andrew Morton
2004-05-24T07:54:12Z

Phy Prabab <phyprabab@yahoo.com> wrote:
>
> Okay, here is the output:
>
> 317955 total
> 0.1302
> 263633 poll_idle
> 4545.3966
> 6764 do_page_fault
> 5.1951
> 3650 kmap_atomic

It's strange that you appear to be using poll_idle(). Maybe it's an error
in the profiler - it sometimes makes mistakes in identifying small
functions.

But if you _are_ using poll_idle() and if your CPU is hyperthreaded then
yes, one "CPU" is going to take a performance hit from the "idle" one.

Is your CPU hyperthreaded? (cat /proc/cpuinfo)

Are you booting with "idle=poll"? Do `dmesg -s 1000000 | grep idle'.