Peter-Jan Gootzen 106e4df120 virtio-fs: improved request latencies when Virtio queue is full
Currently, when the Virtio queue is full, a work item is scheduled
to execute in 1ms that retries adding the request to the queue.
This is a large amount of time on the scale on which a
virtio-fs device can operate. When using a DPU this is around
30-40us baseline without going to a remote server (4k, QD=1).

This patch changes the retrying behavior to immediately filling the
Virtio queue up again when a completion has been received.

This reduces the 99.9th percentile latencies in our tests by
60x and slightly increases the overall throughput, when using a
workload IO depth 2x the size of the Virtio queue and a
DPU-powered virtio-fs device (NVIDIA BlueField DPU).

Signed-off-by: Peter-Jan Gootzen <pgootzen@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Yoray Zack <yorayz@nvidia.com>
Message-Id: <20240517190435.152096-3-pgootzen@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-07-09 08:42:42 -04:00
..
2024-05-29 09:25:15 -07:00
2024-07-02 21:23:00 +02:00
2024-01-11 20:11:35 -08:00
2024-07-01 12:48:28 -07:00
2024-05-13 14:14:05 -07:00
2024-05-21 09:51:42 -07:00
2024-05-20 13:23:43 -07:00
2024-05-21 09:51:42 -07:00
2023-12-29 11:58:34 -08:00
2024-05-21 09:51:42 -07:00
2024-06-28 09:32:33 -07:00
2024-05-25 14:19:01 -07:00
2024-03-27 13:17:15 +01:00
2024-04-23 13:27:43 +02:00
2024-04-23 15:37:02 +02:00
2024-03-12 20:03:34 -07:00
2024-05-02 20:35:57 +02:00
2023-10-30 19:28:19 -10:00
2024-05-21 09:51:42 -07:00
2024-05-23 12:04:36 -07:00
2024-04-25 20:56:20 -07:00
2024-05-10 08:26:31 +02:00
2024-03-12 20:03:34 -07:00
2024-03-15 09:00:09 -07:00
2024-05-02 20:35:57 +02:00
2024-04-17 13:49:44 +02:00
2024-03-11 10:21:06 -07:00
2024-03-13 12:53:53 -07:00
2024-07-01 09:22:08 -07:00
2024-02-02 13:11:49 +01:00
2024-03-12 20:03:34 -07:00
2024-05-02 16:28:20 +02:00
2024-05-24 13:34:07 +02:00
2024-03-26 09:01:18 +01:00
2024-04-10 16:23:02 -06:00
2024-02-15 23:43:47 -05:00