4 ms·
PCIe is more like a packet-switched network than a bus, which is incidentally why things like Thunderbolt (effectively external PCIe) and sillier demonstrations
by userbinator 2mo ago
PCIe is more like a packet-switched network than a bus, which is incidentally why things like Thunderbolt (effectively external PCIe) and sillier demonstrations like https://www.youtube.com/watch?v=q5xvwPa3r7M https://www.youtube.com/watch?v=q5xvwPa3r7M work.
...and with things like https://en.wikipedia.org/wiki/ExpEther https://en.wikipedia.org/wiki/ExpEther , you can get even higher latencies.
- inigyou 2mo agoPretty dumb right? When latency gets this high, you need a more asynchronous design to get any reasonable performance. PCIe is clearly designed with the assumption of latencies a few hundred cycles at most (or usually) - this MMIO register is an extreme outlier. It might be unmapped, and timing out on the hardware side, or it might be converted to an access on some really slow configuration bus.