search for: vhost_rxtx

...dered after loads. So an explicit hardware memory barrier is needed. I hope that is a correct assessment of the situation. (Forgive my x86centricity, I am sure that seems very foreign to kernel hackers.) If this assessment is correct then the DPDK developers might also want to review librte_vhost/vhost_rxtx.c and consider adding a hardware memory barrier between writing used->idx and reading avail->flags. Cheers, -Luke P.S. I notice that the Linux virtio-net driver does not seem to tolerate spurious interrupts, even though the Virtio 1.0 spec requires this ("must"). On 3.13.11-ckt15...

...dered after loads. So an explicit hardware memory barrier is needed. I hope that is a correct assessment of the situation. (Forgive my x86centricity, I am sure that seems very foreign to kernel hackers.) If this assessment is correct then the DPDK developers might also want to review librte_vhost/vhost_rxtx.c and consider adding a hardware memory barrier between writing used->idx and reading avail->flags. Cheers, -Luke P.S. I notice that the Linux virtio-net driver does not seem to tolerate spurious interrupts, even though the Virtio 1.0 spec requires this ("must"). On 3.13.11-ckt15...

...licit hardware memory barrier is needed. > > I hope that is a correct assessment of the situation. (Forgive my > x86centricity, I am sure that seems very foreign to kernel hackers.) > > If this assessment is correct then the DPDK developers might also want to > review librte_vhost/vhost_rxtx.c and consider adding a hardware memory > barrier between writing used->idx and reading avail->flags. > > Cheers, > -Luke > > P.S. I notice that the Linux virtio-net driver does not seem to tolerate > spurious interrupts, even though the Virtio 1.0 spec requires this >...

...gt; hardware memory barrier is needed. > > I hope that is a correct assessment of the situation. (Forgive my > x86centricity, I am sure that seems very foreign to kernel hackers.) > > If this assessment is correct then the DPDK developers might also want to > review librte_vhost/vhost_rxtx.c and consider adding a hardware memory barrier > between writing used->idx and reading avail->flags. > > Cheers, > -Luke I agree, this looks like a bug in dpdk. > P.S. I notice that the Linux virtio-net driver does not seem to tolerate > spurious interrupts, even though...

Hi Nikolay, I poked at src/lib/virtio/virtq.lua a bit - I was surprised to find no explicit CPU memory barriers in the virtq implementation. These are typically required when using virtio on smp machines - the spec actually mention where barriers are necessary. Are the barriers implicit somehow for lua? I'd be curious to learn. Thanks, -- MST

Hi Nikolay, I poked at src/lib/virtio/virtq.lua a bit - I was surprised to find no explicit CPU memory barriers in the virtq implementation. These are typically required when using virtio on smp machines - the spec actually mention where barriers are necessary. Are the barriers implicit somehow for lua? I'd be curious to learn. Thanks, -- MST