search for: _f_next

..._desc(vq, head_id, prev_id,..): > > > grabs a desc from the vq and inserts it to the chain tail (which is indexed > > > by > > > prev_id, probably better to call it tail_id). Then, the new added desc > > > becomes > > > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > > > when it's > > > added to the chain, and set when another desc comes to follow later. > > And this only works if there are multiple rings like > > avail + descriptor ring. > > It won't work e.g. with the proposed new lay...

..._desc(vq, head_id, prev_id,..): > > > grabs a desc from the vq and inserts it to the chain tail (which is indexed > > > by > > > prev_id, probably better to call it tail_id). Then, the new added desc > > > becomes > > > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > > > when it's > > > added to the chain, and set when another desc comes to follow later. > > And this only works if there are multiple rings like > > avail + descriptor ring. > > It won't work e.g. with the proposed new lay...

...functions here: > > 1) virtqueue_add_chain_desc(vq, head_id, prev_id,..): > grabs a desc from the vq and inserts it to the chain tail (which is indexed > by > prev_id, probably better to call it tail_id). Then, the new added desc > becomes > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > when it's > added to the chain, and set when another desc comes to follow later. And this only works if there are multiple rings like avail + descriptor ring. It won't work e.g. with the proposed new layout where writing out a descriptor exposes it imm...

...functions here: > > 1) virtqueue_add_chain_desc(vq, head_id, prev_id,..): > grabs a desc from the vq and inserts it to the chain tail (which is indexed > by > prev_id, probably better to call it tail_id). Then, the new added desc > becomes > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > when it's > added to the chain, and set when another desc comes to follow later. And this only works if there are multiple rings like avail + descriptor ring. It won't work e.g. with the proposed new layout where writing out a descriptor exposes it imm...

...gt;> 1) virtqueue_add_chain_desc(vq, head_id, prev_id,..): >> grabs a desc from the vq and inserts it to the chain tail (which is indexed >> by >> prev_id, probably better to call it tail_id). Then, the new added desc >> becomes >> the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc >> when it's >> added to the chain, and set when another desc comes to follow later. > And this only works if there are multiple rings like > avail + descriptor ring. > It won't work e.g. with the proposed new layout where > writing out...

...; > grabs a desc from the vq and inserts it to the chain tail (which is indexed > > > > > by > > > > > prev_id, probably better to call it tail_id). Then, the new added desc > > > > > becomes > > > > > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > > > > > when it's > > > > > added to the chain, and set when another desc comes to follow later. > > > > And this only works if there are multiple rings like > > > > avail + descriptor ring. > > > &gt...

...; > grabs a desc from the vq and inserts it to the chain tail (which is indexed > > > > > by > > > > > prev_id, probably better to call it tail_id). Then, the new added desc > > > > > becomes > > > > > the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc > > > > > when it's > > > > > added to the chain, and set when another desc comes to follow later. > > > > And this only works if there are multiple rings like > > > > avail + descriptor ring. > > > &gt...

...head_id, prev_id,..): >>>> grabs a desc from the vq and inserts it to the chain tail (which is indexed >>>> by >>>> prev_id, probably better to call it tail_id). Then, the new added desc >>>> becomes >>>> the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc >>>> when it's >>>> added to the chain, and set when another desc comes to follow later. >>> And this only works if there are multiple rings like >>> avail + descriptor ring. >>> It won't work e.g. with the pro...

...t;> grabs a desc from the vq and inserts it to the chain tail (which is indexed >>>>>> by >>>>>> prev_id, probably better to call it tail_id). Then, the new added desc >>>>>> becomes >>>>>> the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc >>>>>> when it's >>>>>> added to the chain, and set when another desc comes to follow later. >>>>> And this only works if there are multiple rings like >>>>> avail + descriptor ring. >>>>...

...exciting! > Dave, given the holiday, attempts to wrap up the 1.1 spec and the > patchset size I would very much appreciate a bit more time for > review. Say until Nov 28? > > > To make this patch set work with below patch set for vhost, > > some hacks are needed to set the _F_NEXT flag in indirect > > descriptors (this should be fixed in vhost): > > > > https://lkml.org/lkml/2018/7/3/33 > > Could you pls clarify - do you mean it doesn't yet work with vhost > because of a vhost bug, and to test it with the linked patches > you had to hack i...

...e. Thanks a lot, this is very exciting! Dave, given the holiday, attempts to wrap up the 1.1 spec and the patchset size I would very much appreciate a bit more time for review. Say until Nov 28? > To make this patch set work with below patch set for vhost, > some hacks are needed to set the _F_NEXT flag in indirect > descriptors (this should be fixed in vhost): > > https://lkml.org/lkml/2018/7/3/33 Could you pls clarify - do you mean it doesn't yet work with vhost because of a vhost bug, and to test it with the linked patches you had to hack in _F_NEXT? Because I do not see _F_...

On Wed, Jul 12, 2017 at 09:29:00PM +0800, Wei Wang wrote: > On 07/12/2017 09:06 PM, Michael S. Tsirkin wrote: > > On Wed, Jul 12, 2017 at 08:40:18PM +0800, Wei Wang wrote: > > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > > > index 28b0e96..9f27101 100644 > > > --- a/include/linux/virtio.h > > > +++ b/include/linux/virtio.h > >

On Wed, Jul 12, 2017 at 09:29:00PM +0800, Wei Wang wrote: > On 07/12/2017 09:06 PM, Michael S. Tsirkin wrote: > > On Wed, Jul 12, 2017 at 08:40:18PM +0800, Wei Wang wrote: > > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > > > index 28b0e96..9f27101 100644 > > > --- a/include/linux/virtio.h > > > +++ b/include/linux/virtio.h > >

...ar. Please let me explain the two functions here: 1) virtqueue_add_chain_desc(vq, head_id, prev_id,..): grabs a desc from the vq and inserts it to the chain tail (which is indexed by prev_id, probably better to call it tail_id). Then, the new added desc becomes the tail (i.e. the last desc). The _F_NEXT flag is cleared for each desc when it's added to the chain, and set when another desc comes to follow later. 2) virtqueue_add_chain(vq, head_id,..): expose the chain to the other end. So, if people want to add a desc and immediately expose it to the other end, i.e. build a single desc chain,...

...ormance test between pktgen (pktgen_sample03_burst_single_flow.sh) > and DPDK vhost (testpmd/rxonly/vhost-PMD) has been done, I saw > ~30% performance gain in packed ring in this case. > > To make this patch set work with below patch set for vhost, > some hacks are needed to set the _F_NEXT flag in indirect > descriptors (this should be fixed in vhost): > > https://lkml.org/lkml/2018/7/3/33 I went over it and I think it's correct spec-wise. I have some ideas for enhancements but let's start with getting this stuff merged first. Acked-by: Michael S. Tsirkin <mst...

...in virtio driver. A performance test between pktgen (pktgen_sample03_burst_single_flow.sh) and DPDK vhost (testpmd/rxonly/vhost-PMD) has been done, I saw ~30% performance gain in packed ring in this case. To make this patch set work with below patch set for vhost, some hacks are needed to set the _F_NEXT flag in indirect descriptors (this should be fixed in vhost): https://lkml.org/lkml/2018/7/3/33 v2 -> v3: - Use leXX instead of virtioXX (MST); - Refactor split ring first (MST); - Add debug helpers (MST); - Put split/packed ring specific fields in sub structures (MST); - Handle normal descrip...

...in virtio driver. A performance test between pktgen (pktgen_sample03_burst_single_flow.sh) and DPDK vhost (testpmd/rxonly/vhost-PMD) has been done, I saw ~30% performance gain in packed ring in this case. To make this patch set work with below patch set for vhost, some hacks are needed to set the _F_NEXT flag in indirect descriptors (this should be fixed in vhost): https://lkml.org/lkml/2018/7/3/33 v2 -> v3: - Use leXX instead of virtioXX (MST); - Refactor split ring first (MST); - Add debug helpers (MST); - Put split/packed ring specific fields in sub structures (MST); - Handle normal descrip...