Re: Watchdog timer per hart?


Greg Favor
 

A core-level watchdog can mean quite different things to different people and their core designs.  In some cases this "watchdog" would be a micro-architectural thing that, for example, recognizes that the core is not making forward progress and would temporarily invoke some low-performance uarch mechanism that guarantees forward progress (out of the circumstances currently causing livelock).  Although the details of that very much depend on what types of livelock causes one is concerned about.  In other cases this "watchdog" might generate a local interrupt to take the core into a "lack of forward progress" software handler; or a global interrupt to inform someone else that this core is livelocked.

In general, there's an enormous range of possibilities as to what a core-level watchdog means.  And an enormous range as to what one is trying to accomplish or defend against.

Greg


On Wed, Mar 2, 2022 at 12:09 PM James Robinson <jrobinson@...> wrote:
Hi Aaron,

Thanks for the response. Would you be able to give any more details on how a core level watchdog would differ from a platform level one?

James

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