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

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Fri, 10 Feb 2023 19:09:12 +0100

Alexander Lobakin <[email-masked]> 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 :)

-Toke