# Re: mpc880 linux-2.6.32 slow running processes

- From: Joakim Tjernlund \<hidden\>
- Date: 2011-01-10 16:55:17 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2011/01/9463168
- Thread: https://ratatoskr.run/linuxppc-dev/2011/01/9463122/t.md

```text
Rafael Beims [ref] wrote on 2011/01/10 17:35:38:
> >
> > Once you have tested it and it works, please send a patch to remove the 8xx workaround.
> > Make sure Scott is cc:ed
> >
> >
>
> I tested linux-2.6.33 on my ppc880 board today, and even without the
> slowdown.patch applied, the board runs processes with good
> performance.
> It really seems that the problem is solved from linux-2.6.33 on.
>
> I'm not sure what you mean by sending a patch to remove the
> workaround. The only thing that I did in the 2.6.32 version was to
> apply the slowdown.patch attached in the message from Michael.
>
> Could you clarify please?

Yes, this part in arch/powerpc/mm/pgtable.c:
#ifdef CONFIG_8xx
			/* On 8xx, cache control instructions (particularly
			 * "dcbst" from flush_dcache_icache) fault as write
			 * operation if there is an unpopulated TLB entry
			 * for the address in question. To workaround that,
			 * we invalidate the TLB here, thus avoiding dcbst
			 * misbehaviour.
			 */
			/* 8xx doesn't care about PID, size or ind args */
			_tlbil_va(addr, 0, 0, 0);
#endif /* CONFIG_8xx */

Should be removed in >= 2.6.33 kernels.
My 8xx TLB work fixes this problem more efficiently.

    Jocke
```