Re: [PATCH bpf-next 0/6] ice: post-mbuf fixes

[Alexander Lobakin]

From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Date: Fri, 10 Feb 2023 19:09:12 +0100

> Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> writes:
> 
>> The set grew from the poor performance of %BPF_F_TEST_XDP_LIVE_FRAMES
>> when the ice-backed device is a sender. Initially there were around
>> 3.3 Mpps / thread, while I have 5.5 on skb-based pktgen...
>>
>> After fixing 0005 (0004 is a prereq for it) first (strange thing nobody
>> noticed that earlier), I started catching random OOMs. This is how 0002
>> (and partially 0001) appeared.
>> 0003 is a suggestion from Maciej to not waste time on refactoring dead
>> lines. 0006 is a "cherry on top" to get away with the final 6.7 Mpps.
>> 4.5 of 6 are fixes, but only the first three are tagged, since it then
>> starts being tricky. I may backport them manually later on.
>>
>> TL;DR for the series is that shortcuts are good, but only as long as
>> they don't make the driver miss important things. %XDP_TX is purely
>> driver-local, however .ndo_xdp_xmit() is not, and sometimes assumptions
>> can be unsafe there.
>>
>> With that series and also one core code patch[0], "live frames" and
>> xdp-trafficgen are now safe'n'fast on ice (probably more to come).
> 
> Nice speedup! And cool to see that you're playing around with
> xdp-trafficgen :)

It's not only good for bombing receivers without any special HW, but
also for uncovering problems with XDP in drivers and/or kernel core,
as I can see :D

> 
> -Toke
>

Thanks,
Olek