11–20 of 22 posts
ooh no more DPDK, this will make it a lot easier. I just started working with trex but it's all really complicated. Going to give this a try
ooh no more DPDK, this will make it a lot easier. I just started working with trex but it's all really complicated. Going to give this a try
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
Earlier quoted context omitted.
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
I think you're correct. Not really aware of any real limitations, other than it's slightly slower than dpdk (it's not a complete bypass), but at a much easier ease of use.
Earlier quoted context omitted.
I think you're correct. Not really aware of any real limitations, other than it's slightly slower than dpdk (it's not a complete bypass), but at a much easier ease of use.
AF_XDP kind of is a complete bypass, right? RX get scooped right off the DMA buffer for the card, and TX get shoved right back in.
The difference I was getting at vs DPDK is that the kernel NIC driver/NAPI/XDP path is still involvd. With DPDK the userspace PMD is effectively driving the NIC and accessing the queues directly.
either way, it's great and everyone should use it :) that is assuming they have a use case for it. The use-cases are perhaps somewhat limited as it also bypasses the kernel tcp-ip stack, so you gotta do a lot yourself.
ooh no more DPDK, this will make it a lot easier. I just started working with trex but it's all really complicated. Going to give this a try
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
Disclosure: Ostinato creator here.
ooh no more DPDK, this will make it a lot easier. I just started working with trex but it's all really complicated. Going to give this a try
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
ooh no more DPDK, this will make it a lot easier. I just started working with trex but it's all really complicated. Going to give this a try
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
I need to check about the af_xdp ecosystem around fragmentation/reassembly in UDP too, every time I needed something there DPDK had it, often with an offload path.
Some silly stuff in DPDK are very useful for testing too (in-memory devices).
Also I'm not clear on the virtualization story on af_xdp, with dpdk I got something working at full blast 400G in VMs with little (but finnicky) work.
Earlier quoted context omitted.
I think, and I'm saying this in part to get someone to correct me, that post-XDP (so 5 years or so now) DPDK is basically obsolete. Is there a circumstance where it would make sense to start from DPDK rather than XDP?
I think access to offload engines is a big part of the appeal of dpdk still, especially for me all the GPUdirect nvidia-only packet steerer. I need to check about the af_xdp ecosystem around fragmentation/reassembly in UDP too, every time I needed something there DPDK had it, often with an offload path. Some silly stuff in DPDK are very useful for testing too (in-memory devices). Also I'm not clear on the virtualizat…
That’s very interesting, thank you for sharing. Looks like it could be a very useful tool for testing high performance networking. I wonder if something similar could be done using TC BPF instead of AF_XDP? My only reservation about AF XDP is that it requires a special NIC to support it, so it may not be useful for a “regular Joe” user. I wonder if TC BPF would also work since it similarly bypasses the Kernel network…
You can, but the interesting thing about AF_XDP is that you've got a userland path to writing directly to the card's DMA buffers; TC BPF still allocates an skbuff for every packet you send.
AF_XDP is also available in older kernels, but with recent enough kernels (zero-copy receive is a recent addition) and with a good NIC, liburing should provide a similar performance.
Earlier quoted context omitted.
I think access to offload engines is a big part of the appeal of dpdk still, especially for me all the GPUdirect nvidia-only packet steerer. I need to check about the af_xdp ecosystem around fragmentation/reassembly in UDP too, every time I needed something there DPDK had it, often with an offload path. Some silly stuff in DPDK are very useful for testing too (in-memory devices). Also I'm not clear on the virtualizat…
I am corrected. Thanks! :)
A lot of the socket featureset of io_uring seems available in AF_XDP https://docs.kernel.org/networking/af_xdp.html which shows lots of progress since I looked last.
To get an idea of what DPDK gives low-level access to there is the overview https://doc.dpdk.org/guides/nics/features.html and my "favorite annual terabit read" https://doc.dpdk.org/guides/nics/mlx5.html#mlx5-net-features for NVIDIA NICs. Broadcom has some fun stuff too. The first time you hit top RX speed (2x400G my latest) with only one busy core (yay DMA engines) is always a thrill.