Messages in this thread | | | Date | Wed, 15 Dec 2021 18:54:29 +0000 | Subject | Re: [PATCH v3] cgroup/bpf: fast path skb BPF filtering | From | Pavel Begunkov <> |
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On 12/15/21 18:24, sdf@google.com wrote: > On 12/15, Pavel Begunkov wrote: >> On 12/15/21 17:33, sdf@google.com wrote: >> > On 12/15, Pavel Begunkov wrote: >> > > On 12/15/21 16:51, sdf@google.com wrote: >> > > > On 12/15, Pavel Begunkov wrote: >> > > > > � /* Wrappers for __cgroup_bpf_run_filter_skb() guarded by cgroup_bpf_enabled. */ >> > > > > � #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb)����������������� \ >> > > > > � ({����������������������������������������� \ >> > > > > ����� int __ret = 0;��������������������������������� \ >> > > > > -��� if (cgroup_bpf_enabled(CGROUP_INET_INGRESS))������������� \ >> > > > > +��� if (cgroup_bpf_enabled(CGROUP_INET_INGRESS) && sk &&������������� \ >> > > > > +������� CGROUP_BPF_TYPE_ENABLED((sk), CGROUP_INET_INGRESS))���������� \ >> > > > >> > > > Why not add this __cgroup_bpf_run_filter_skb check to >> > > > __cgroup_bpf_run_filter_skb? Result of sock_cgroup_ptr() is already there >> > > > and you can use it. Maybe move the things around if you want >> > > > it to happen earlier. >> > >> > > For inlining. Just wanted to get it done right, otherwise I'll likely be >> > > returning to it back in a few months complaining that I see measurable >> > > overhead from the function call :) >> > >> > Do you expect that direct call to bring any visible overhead? >> > Would be nice to compare that inlined case vs >> > __cgroup_bpf_prog_array_is_empty inside of __cgroup_bpf_run_filter_skb >> > while you're at it (plus move offset initialization down?). > >> Sorry but that would be waste of time. I naively hope it will be visible >> with net at some moment (if not already), that's how it was with io_uring, >> that's what I see in the block layer. And in anyway, if just one inlined >> won't make a difference, then 10 will. > > I can probably do more experiments on my side once your patch is > accepted. I'm mostly concerned with getsockopt(TCP_ZEROCOPY_RECEIVE). > If you claim there is visible overhead for a direct call then there > should be visible benefit to using CGROUP_BPF_TYPE_ENABLED there as > well.
Interesting, sounds getsockopt might be performance sensitive to someone.
FWIW, I forgot to mention that for testing tx I'm using io_uring (for both zc and not) with good submission batching.
-- Pavel Begunkov
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