Re: [Xen-ia64-devel] RFC: ptc.ga implementation for SMP-g

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Mardi 04 Avril 2006 15:56, Xu, Anthony a écrit :
> Hi Tristan,
> Sorry for late response.
>
> Let's first make sure our understanding of ptc.ga is correct.
> Assume there are two LPs on one box, we call them LP1 and LP2,
> And rr7=0x107 on LP1, rr7=0x207 on LP2,
> And below code segment is executed at LP1
>       movl    R2=0xe000000000000000;
>      mov r3=16<<2;
>       ptc.ga r2,r3;
> The result on LP1 is, all tlb entries with rid=0x107 which are overlapped
> with (0xe000000000000000~0xe000000000010000) are purged.
> The result on LP2 should be same with that on LP1.
>
> But according to this patch,
> The result on LP2 is, all tlb entries with rid=0x207 which are overlapped
> with (0xe000000000000000~0xe000000000010000) are purged.
> This is not the desirable result of ptc.ga.
>
> IMO, when using IPI to emulate ptc.ga, the related rid should be passed to
> other LPs as a parameter.
dtlb and itlb are cleared unconditionnaly.
However you are right, the VHPT entry is not the good one.  I think this is a 
good reason not to do it with the IPI, but to clear directly the entry.

Tristan.


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