Hi Michael,
this series is marked as "Not Applicable" for the net-next tree:
https://patchwork.kernel.org/project/netdevbpf/patch/20240730-pinna-v4-2-5c9179164db5@xxxxxxxxxxx/
Actually this is more about the virtio-vsock driver, so can you queue
this on your tree?
Thanks,
Stefano
On Tue, Jul 30, 2024 at 09:47:30PM GMT, Luigi Leonardi via B4 Relay wrote:
This series introduces an optimization for vsock/virtio to reduce latency
and increase the throughput: When the guest sends a packet to the host,
and the intermediate queue (send_pkt_queue) is empty, if there is enough
space, the packet is put directly in the virtqueue.
v3->v4
While running experiments on fio with 64B payload, I realized that there
was a mistake in my fio configuration, so I re-ran all the experiments
and now the latency numbers are indeed lower with the patch applied.
I also noticed that I was kicking the host without the lock.
- Fixed a configuration mistake on fio and re-ran all experiments.
- Fio latency measurement using 64B payload.
- virtio_transport_send_skb_fast_path sends kick with the tx_lock acquired
- Addressed all minor style changes requested by maintainer.
- Rebased on latest net-next
- Link to v3: https://lore.kernel.org/r/20240711-pinna-v3-0-697d4164fe80@xxxxxxxxxxx
v2->v3
- Performed more experiments using iperf3 using multiple streams
- Handling of reply packets removed from virtio_transport_send_skb,
as is needed just by the worker.
- Removed atomic_inc/atomic_sub when queuing directly to the vq.
- Introduced virtio_transport_send_skb_fast_path that handles the
steps for sending on the vq.
- Fixed a missing mutex_unlock in error path.
- Changed authorship of the second commit
- Rebased on latest net-next
v1->v2
In this v2 I replaced a mutex_lock with a mutex_trylock because it was
insidea RCU critical section. I also added a check on tx_run, so if the
module is being removed the packet is not queued. I'd like to thank Stefano
for reporting the tx_run issue.
Applied all Stefano's suggestions:
- Minor code style changes
- Minor commit text rewrite
Performed more experiments:
- Check if all the packets go directly to the vq (Matias' suggestion)
- Used iperf3 to see if there is any improvement in overall throughput
from guest to host
- Pinned the vhost process to a pCPU.
- Run fio using 512B payload
Rebased on latest net-next
---
Luigi Leonardi (1):
vsock/virtio: avoid queuing packets when intermediate queue is empty
Marco Pinna (1):
vsock/virtio: refactor virtio_transport_send_pkt_work
net/vmw_vsock/virtio_transport.c | 144 +++++++++++++++++++++++++--------------
1 file changed, 94 insertions(+), 50 deletions(-)
---
base-commit: 1722389b0d863056d78287a120a1d6cadb8d4f7b
change-id: 20240730-pinna-db8cc1b8b037
Best regards,
--
Luigi Leonardi <luigi.leonardi@xxxxxxxxxxx>
