[PVE-User] High load on cpu0 with 3.10 pve kernel on proxmox 3.4

Falko Trojahn trojahn+proxmox at pluspol.info
Tue Sep 1 15:19:48 CEST 2015

Am 01.09.2015 um 14:45 schrieb Thomas Lamprecht:
> There is an huge amount of interrupts from the network card and also
> from your raid.
> I'd guess that the main problem it's your network card, make sure the
> driver of eth0 and eth3 are configured and installed correctly.

Ok, I'll check'em again.

What do you think about compiling a newer kernel, since there seems
to be a patch for specially this problem?

Since commit 77873803363c "net_dma: mark broken" we no longer pin dma
engines active for the network-receive-offload use case. As a result
the ->free_chan_resources() that occurs after the driver self test no
longer has a NET_DMA induced ->alloc_chan_resources() to back it up. A
late firing irq can lead to ksoftirqd spinning indefinitely due to the
tasklet_disable() performed by ->free_chan_resources(). Only
->alloc_chan_resources() can clear this condition in affected kernels.

This problem has been present since commit 3e037454bcfa "I/OAT: Add
support for MSI and MSI-X" in 2.6.24, but is now exposed. Given the
NET_DMA use case is deprecated we can revisit moving the driver to use
threaded irqs. ...




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