On Thu, Aug 20, 2020 at 03:45:43PM +0200, Cédric Le Goater wrote: > Hello, > > > When QEMU switches to the XIVE interrupt mode, it creates all the > guest interrupts at the level of the KVM device. These interrupts are > backed by real HW interrupts from the IPI interrupt pool of the XIVE > controller. > > Currently, this is done from the QEMU main thread, which results in > allocating all interrupts from the chip on which QEMU is running. IPIs > are not distributed across the system and the load is not well > balanced across the interrupt controllers. > > Change the vCPU IPI allocation to run from the vCPU context. The > associated XIVE IPI interrupt will be allocated on the chip on which > the vCPU is running and improve distribution of the IPIs in the system. > When the vCPUs are pinned, this will make the IPI local to the chip of > the vCPU. It will reduce rerouting between interrupt controllers and > gives better performance. > > > I did some basic migration testing with the 'dual' and 'xive' modes, > also tried CPU hoplug. I haven't tried migration with older pseries > machine.
LGTM, applied to ppc-for-5.2. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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