* bpf: add BPF_CGROUP_SOCK_OPS callback that is executed on every RTT (commit: 23729ff23186424)
@ 2024-07-25 19:37 Rao Shoaib
2024-07-26 3:29 ` Stanislav Fomichev
0 siblings, 1 reply; 2+ messages in thread
From: Rao Shoaib @ 2024-07-25 19:37 UTC (permalink / raw)
To: sdf, Eric Dumazet, priyarjha, ycheng, soheil, daniel; +Cc: netdev, bpf
Hi Stanislav,
I have a question about the placement of tcp_bpf_rtt() call in
tcp_rtt_estimator(). Why is the call made before the assignment
tp->srtt_us = max(1U, srtt);
How is the attached eBPF program suppose the get the new value?
Thanks,
Shoaib
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: bpf: add BPF_CGROUP_SOCK_OPS callback that is executed on every RTT (commit: 23729ff23186424)
2024-07-25 19:37 bpf: add BPF_CGROUP_SOCK_OPS callback that is executed on every RTT (commit: 23729ff23186424) Rao Shoaib
@ 2024-07-26 3:29 ` Stanislav Fomichev
0 siblings, 0 replies; 2+ messages in thread
From: Stanislav Fomichev @ 2024-07-26 3:29 UTC (permalink / raw)
To: Rao Shoaib
Cc: sdf, Eric Dumazet, priyarjha, ycheng, soheil, daniel, netdev, bpf
On 07/25, Rao Shoaib wrote:
> Hi Stanislav,
>
> I have a question about the placement of tcp_bpf_rtt() call in
> tcp_rtt_estimator(). Why is the call made before the assignment
>
> tp->srtt_us = max(1U, srtt);
>
> How is the attached eBPF program suppose the get the new value?
Take a look at the way tcp_bpf_rtt is invoked. It gets mrtt_us
and srtt arguments. Those are passed via bpf_sock_ops args field.
See tools/testing/selftests/bpf/progs/tcp_rtt.c. Hope that helps!
^ permalink raw reply [flat|nested] 2+ messages in thread
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2024-07-25 19:37 bpf: add BPF_CGROUP_SOCK_OPS callback that is executed on every RTT (commit: 23729ff23186424) Rao Shoaib
2024-07-26 3:29 ` Stanislav Fomichev
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