A ring left with a burst: the interrupt raised, the handler never run. Measured, 2026-10-21¶
Issue 361: with the trigger on, a few times an hour, a burst landed in one of the XGS 3300's receive rings and waited there until the receive watchdog's next sweep - up to a period, 50 ms - with TCP covering the gap every time. Two instrument builds on 2026-10-13 read the block's registers at such a stall: the ring's interrupt status set, the vector unmasked, nothing pending. The reading drawn from them - a status a visit had left up gives the next packet no edge - is withdrawn below. The ring was left clean; the block raised its interrupt; the host never ran the handler. Why the message does not arrive is still not known. What changed is that the host no longer waits for it: it looks at every ring's head buffer each tick.
The whole page, with how it was taken and what it does not show: A ring left with a burst: the interrupt raised, the handler never run. Measured, 2026-10-21.
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