Jesper Dangaard Brouer wrote:
On 12/3/23 17:51, Song Yoong Siang wrote:
This patch enables Launch Time (Time-Based Scheduling) support to XDP zero copy via XDP Tx metadata framework.
Signed-off-by: Song Yoong Siangyoong.siang.song@intel.com
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 2 ++
As requested before, I think we need to see another driver implementing this.
I propose driver igc and chip i225.
The interesting thing for me is to see how the LaunchTime max 1 second into the future[1] is handled code wise. One suggestion is to add a section to Documentation/networking/xsk-tx-metadata.rst per driver that mentions/documents these different hardware limitations. It is natural that different types of hardware have limitations. This is a close-to hardware-level abstraction/API, and IMHO as long as we document the limitations we can expose this API without too many limitations for more capable hardware.
I would assume that the kfunc will fail when a value is passed that cannot be programmed.
What is being implemented here already exists for qdiscs. The FQ qdisc takes a horizon attribute and
" when a packet is beyond the horizon at enqueue() time: - either drop the packet (default policy) - or cap its delivery time to the horizon. " commit 39d010504e6b ("net_sched: sch_fq: add horizon attribute")
Having the admin manually configure this on the qdisc based on off-line knowledge of the device is more fragile than if the device would somehow signal its limit to the stack.
But I don't think we should add enforcement of that as a requirement for this xdp extension of pacing.