Re: MSI interrupts

In article <b201b9212700f9359a831e03b1d60cef@www.novabbs.org>,
MitchAlsup1 <mitchalsup@aol.com> wrote:

On Tue, 25 Mar 2025 13:45:39 +0000, Scott Lurndal wrote:
>

mitchalsup@aol.com (MitchAlsup1) writes:

>

Nothing gets lost.

>
This isn't a hardware transaction.   If the thread has updated data
and you take away the lock, the system is now inconsistent
and nasal daemons will ensue.

>
In HW there is a little thing known as branch misprediction repair,
where all the work done is made to appear as if those instructions
were never executed to begin with. The size of the branch mispredict
window is on the order of 300 instructions now.
>
With Spectré and Meltdown even cache updates must be delayed until
after the causing instruction retires.

But again, that's irrelevant.  The "critical sections" in
question here are software abstractions created by system
software.  What you're describing is at the microarchitectural
level; two totally different worlds.  I think the fundamental
mismatch here is that you're trying to apply this solution you
have created for something at the uarch level to a problem at
the systems software level.  It's jut not a good fit.

- Dan C.