Re: [bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node
From: Marc Zyngier <maz@kernel.org>
Date: 2021-07-22 12:54:05
Also in:
linux-iommu, linux-nvme, lkml
On 2021-07-22 12:12, John Garry wrote: Hi John, [...]
Your kernel log should show:
[ 0.000000] GICv3: Pseudo-NMIs enabled using forced ICC_PMR_EL1
synchronisation
Unrelated, but you seem to be running with ICC_CTLR_EL3.PMHE set,
which makes the overhead of pseudo-NMIs much higher than it should be
(you take a DSB SY on each interrupt unmasking).
If you are not using 1:N distribution of SPIs on the secure side,
consider turning that off in your firmware. This should make NMIs
slightly more pleasant to use.
M.
--
Jazz is not dead. It just smells funny...
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