Hi all,

There were a couple of issues you asked about, and I didn't address fully during the talk, so here we go:

Q: How do you detect a PCIe peripheral?

A: The answer is embarrassingly simple: lspci -vv gives you everything you wanted to know (and a lot you didn't). In particular, in the Capabilities section, if there's a capability name with "Express" in it appearing, it's a PCIe device.

Q: What about speed and performance?

A: lspci -vv again. It supplies both the (maximal) lane number and lane speed. As for packet overhead and squeezing every drop of bandwidth from the hardware, I talk about that in a recent post:


As for the connection between my calculated upper limit (219 MB/sec) and reality, I consistently get 205 MB/sec with long dd transfers from hardware to PC (/dev/null, that is). Assuming I did nothing stupid, that's most likely the real-life limit. The CPU was at about 50% usage, and hardware writes way ahead of the read cursor, so I believe in this number.


Web: http://www.billauer.co.il

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