On 1/2/26 1:59 PM, Bryan O'Donoghue wrote:

On 02/01/2026 12:00, Konrad Dybcio wrote:

quoted

quoted

Is there an io-fabric in the world which exceeds 1 microsecond to perform a write transaction ?

Writes on arm64 aren't usually observable from the remote endpoint when
you would expect them to, they can be buffered unless there's an explicit
readback right afterwards (which creates a dependency that the processor
will fulfill)

I don't mean write-combining cache, I mean posted versus non-posted writes which is a feature of the front-side-bus :)

Writes are posted (Device-nGnRE, note the E attribute is set)

https://documentation-service.arm.com/static/63a43e333f28e5456434e18b

Konrad