mpc880 linux-2.6.32 slow running processes
joakim.tjernlund at transmode.se
Tue Jan 11 03:55:11 EST 2011
Rafael Beims <rbeims at gmail.com> 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
> 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:
/* 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
/* 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.
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