Re: [PATCH 0/5] Threaded MSI interrupt for VFIO PCI device

[Alex Williamson]

On Thu, 2015-12-03 at 10:22 -0800, Yunhong Jiang wrote:
> When assigning a VFIO device to a KVM guest with low latency requirement, it  
> is better to handle the interrupt in the hard interrupt context, to reduce 
> the context switch to/from the IRQ thread.
> 
> Based on discussion on https://lkml.org/lkml/2015/10/26/764, the VFIO msi 
> interrupt is changed to use request_threaded_irq(). The primary interrupt 
> handler tries to set the guest interrupt atomically. If it fails to achieve 
> it, a threaded interrupt handler will be invoked.
> 
> The irq_bypass manager is extended for this purpose. The KVM eventfd will 
> provide a irqbypass consumer to handle the interrupt at hard interrupt 
> context. The producer will invoke the consumer's handler then.

Do you have any performance data?  Thanks,

Alex

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/