Re: [GIT PULL] parisc architecture updates for v4.3

From: Guy Harris
Date: Tue Nov 03 2015 - 18:52:00 EST

On Nov 3, 2015, at 3:43 PM, Guy Harris <guy@xxxxxxxxxxxx> wrote:

> To which particular PA-RISC processor are you referring? It might not be the same on all processors.

Chapter 3 "Addressing and Access Control" of PA-RISC 2.0 Architecture:


A consistent software view of cache operation requires that implementations never write a clean cache line back to memory. (A cache line can be 16, 32, or 64 bytes in length.) Clean means ânot stored intoâ as opposed to ânot changedâ. Dirty means âstored intoâ. A cache line which was stored into in such a way that it was unchanged is considered to be dirty.

so, architecturally, it can be 16, 32, or 64 bytes.

I'm not sure what

When Linux says 'line size' it generally means the cache ownership line size: the minimum block the inter cpu coherence operates on. Most of the architectural evidence for PA systems suggests that this is 16

from the mail message cited means when it speaks of architectural evidence; is that line size different from the line size in the PA-RISC 2.0 Architecture manual? That line size presumably isn't the burst size:

128 seems to be the cache burst fill size (the number of bytes that will be pulled into the
cache by a usual operation touching any byte in the area).--
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