On 2020/7/28 下午12:23, Zhu Lingshan wrote:
This series intends to implement IRQ offloading for vhost_vdpa. By the feat of irq forwarding facilities like posted interrupt on X86, irq bypass can help deliver interrupts to vCPU directly. vDPA devices have dedicated hardware backends like VFIO pass-throughed devices. So it would be possible to setup irq offloading(irq bypass) for vDPA devices and gain performance improvements. In my testing, with this feature, we can save 0.1ms in a ping between two VFs on average. changes from V3: (1)removed vDPA irq allocate/free helpers in vDPA core. (2)add a new function get_vq_irq() in struct vdpa_config_ops, upper layer driver can use this function to: A. query the irq numbner of a vq. B. detect whether a vq is enabled. (3)implement get_vq_irq() in ifcvf driver. (4)in vhost_vdpa, set_status() will setup irq offloading when setting DRIVER_OK, and unsetup when receive !DRIVER_OK. (5)minor improvements.
Ok, I think you can go ahead to post a V5. It's not bad to start with get_vq_irq() and we can do any changes afterwards if it can work for some cases.
Thanks
