Nicolas Droux wrote:
[Bcc'ed [email protected] and
[email protected]]
I am pleased to announce the availability of the first revision of the
"Crossbow APIs for Device Drivers" document, available at the following
location:
I recently ported a 10GbE driver to Crossbow. My driver currently
has a single ring-group, and a configurable number of rings. The
NIC hashes received traffic to the rings in hardware.
I'm having a strange issue which I do not see in the non-crossbow
version of the driver. When I run TCP benchmarks, I'm seeing
what seems like packet loss. Specifically, netstat shows
tcpInUnorderBytes and tcpInDupBytes increasing at a rapid rate,
and bandwidth is terrible (~1Gb/s for crossbow, 7Gb/s non-crossbow
on the same box with the same OS revision).
The first thing I suspected was that packets were getting dropped
due to my having the wrong generation number, but a dtrace probe
doesn't show any drops there.
Now I'm wondering if perhaps the interupt handler is in
the middle of a call to mac_rx_ring() when interrupts
are disabled. Am I supposed to ensure that my interrupt handler is not
calling mac_rx_ring() before my rx_ring_intr_disable()
routine returns? Or does the mac layer serialize this?
Thanks,
Drew
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