Re: Extreme system overhead on large IP27

[mlachwani <mlachwani@mvista.com>]

Hi Atsushi,

I tried out your patch on the SWARM SMP and it works.

thanks,
Manish Lachwani

Atsushi Nemoto wrote:
> On Thu, 26 Oct 2006 00:42:16 -0700 (PDT), Manish Lachwani <m_lachwani@yahoo.com> wrote:
>   
>> It could be that I am seeing a similar issue on the
>> SWARM board (sb1250) as well. Your patch removed the
>> shifts for mip_hpt_frequency from
>> arch/mips/sibyte/sb1250/time.c and in the
>> sb1250_hpt_read(). The Sibyte HPT is 1 Mhz. However,
>> when I added those shifts back, I did not see any
>> issues with the system clock. I could possibly try out
>> your patch with lower clocksource shift values and see
>> if the system clock is still wrong.
>>     
>
> I just sent the patch.  Please try it.
>
>   
>> Btw, the clocksource changes seem to work well on the
>> BCM 1480 based board. 
>>     
>
> Thanks, good news!
>
> As Ralf pointed out, current code still problematic on some SMP
> system, but I think IP27, SB1250, BCM1480 should be OK now while their
> mips_hpt_read are not using per-CPU cp0 timers.
>
> ---
> Atsushi Nemoto
>
>