[CentOS] Intel 82579V ethernet nic using only one IRQ? (Dual TX RX queues)

Sun Jun 9 17:06:13 UTC 2013
Tilman Schmidt <t.schmidt at phoenixsoftware.de>

Am 09.06.2013 06:46, schrieb Alex Flex:
> Hello CentOS Community,
> So I bought a NIC (using the  Intel 82579V chipset) that supports Dual 
> RX and TX queues , my goal with that is so iam able to see and use two 
> IRQs in /proc/interrupts and hence be able to take advantage of 2 cores 
> on my CPU. Instead I only see one IRQ being used, and hence only one CPU 
> core.. Please see below.

First, yes, the NIC will only use one IRQ. That is as it should be.

Second, no, that doesn't mean that only one CPU core will be used.

Very little work is done inside the ISR, because that work must be
strictly serialized. The bulk of the work is done outside interrupt
context, and that work is distributed over the CPU cores by the
scheduler. Distributing the IRQs would unnecessarily complicate
things without buying you any performance improvement.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 261 bytes
Desc: OpenPGP digital signature
URL: <http://lists.centos.org/pipermail/centos/attachments/20130609/73a45528/attachment-0004.sig>