Hi ARM专家们,有几个问题请教一下:
1、PoC是所有Agents能看到同一个memory copy的点,通常是external memory;CCN-5xx HN-F中实现了PoC,
用于管理RN-Fs间的coherency,假如CPU发出带PoC属性的cache maintenance操作,是否可以maintenance L3?
2、如果CPU发出的是带PoU但是带Inner-Shareable属性的cache maintenance操作,此时是否会maintenance L3?
因为CPU接口规定,如果是BROADCASTINNER=1,则BROADCASTOUTER也必须是1。
3、CCN-5xx L3中特别注明指令是pseudo-inclusive,这个与inclusive差别在哪呢?
4、DEN0024A_v8_architecture_PG.pdf文档p214,Table 14-1中,用Set/Way来maintenance cache不带Broadcast
可以理解,但为啥DC IVAC, Xt是一定Broadcast,而DC CVAC, Xt仅是Maybe Broadcast?
Hello Steven,
>1、PoC是所有Agents能看到同一个memory copy的点,通常是external memory;CCN-5xx HN-F中实现了PoC,
> 用于管理RN-Fs间的coherency,假如CPU发出带PoC属性的cache maintenance操作,是否可以maintenance L3?
Yes. See CCN-504 TRM section 4.3.
>2、如果CPU发出的是带PoU但是带Inner-Shareable属性的cache maintenance操作,此时是否会maintenance L3?
> 因为CPU接口规定,如果是BROADCASTINNER=1,则BROADCASTOUTER也必须是1。
In ARMv8, I only see one type of PoU+Inner Shareable operation:
IC IALLUIS
Assuming BROADCASTINNER=1, this operation would generate a DVM operation on the cluster's master interface. CCN-5xx would broadcast it to other clusters.
The L3 is not affected.
>3、CCN-5xx L3中特别注明指令是pseudo-inclusive,这个与inclusive差别在哪呢?
Pseudo-inclusive means not strictly inclusive. So it is possible that an instruction line does not exist in L1/L2, but exists in L3.
>4、DEN0024A_v8_architecture_PG.pdf文档p214,Table 14-1中,用Set/Way来maintenance cache不带Broadcast
> 可以理解,但为啥DC IVAC, Xt是一定Broadcast,而DC CVAC, Xt仅是Maybe Broadcast?
---> zenonxiu for question #4.
Regards,
Xingguang