On 10/12/2020 11:50 AM, Thomas Gleixner wrote:
On Mon, Oct 12 2020 at 11:58, Bjorn Helgaas wrote:
On Mon, Oct 12, 2020 at 09:49:37AM -0600, Chris Friesen wrote:
I've got a linux system running the RT kernel with threaded irqs. On
startup we affine the various irq threads to the housekeeping CPUs, but I
recently hit a scenario where after some days of uptime we ended up with a
number of NVME irq threads affined to application cores instead (not good
when we're trying to run low-latency applications).
These threads and the associated interupt vectors are completely
harmless and fully idle as long as there is nothing on those isolated
CPUs which does disk I/O.
Some of the irq threads are affined (by the kernel presumably) to
multiple CPUs (nvme1q2 and nvme0q2 were both affined 0x38000038, a
couple of other queues were affined 0x1c00001c0).
In this case could disk I/O submitted by one of those CPUs end up
interrupting another one?
Chris
