Re: Help understanding slow down

[Phy Prabab]

Andrew,

I have turned HT off in the bios (caused non
deterministic performance) and I did not configure the
kernel for SMT.  Additionally, looking at dmesg shows
no idle-poll (and I do not boot the kernel with
idle-poll).  
Should I post my config for this kernel?

Thank you for your time.
Phy
--- Andrew Morton <akpm@xxxxxxxx> wrote:
> Phy Prabab <phyprabab@xxxxxxxxx> 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'.
> 


	
		
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