On 13.04 22:15, Manuel Bouyer wrote:
On Mon, Apr 13, 2026 at 03:03:01PM -0400, Greg Troxel wrote:Staffan Thomen <staffan%shangtai.net@localhost> writes:
[...]
The system is not yet in production so I can do tests for a brief time if necessary.I (who is unlikely to fix this) would be interested inwhat is the highest number of cpus that is stable? even roughly from binary search, might be interesting.
Greg: 40 an 20 were too many 10 booted. But this might be highly variable from how many pseudo-interrupts are needed on the cpus, and these seem to use a lot. The standard msgbuf is too small to fit all the boot messages for all the stuff going on.
what is the value of NR_PIRQS in GENERIC and XEN3_DOM0? Is this as simple as a default being different?NR_PIRQS doens't exists in GENERIC. It's an array mapping physical IRQs to Xen events. An array doesn't scale well on hardware with lots of core; something else is needed here.
No need to rush to fix this on my account, although I suppose this could be made to dynamically reallocate itself either in chunks or singly as needed when a new one is discovered? Presumably it's a lookup table that is generated on boot and then never changes. Then again I know next to nothing about kernel programming and even less of xen, only a suspicion that it might be a more restricted environment. Staffan
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