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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alexei Starovoitov <ast@fb.com>, Martin Lau <kafai@fb.com>,
	Eric Dumazet <eric.dumazet@gmail.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	David Miller <davem@davemloft.net>,
	Kernel Team <Kernel-team@fb.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next 09/13] bpf: Add BPF_FUNC_jiffies
Date: Mon, 16 Dec 2019 16:34:08 -0800	[thread overview]
Message-ID: <d34fddb1-4477-12e7-8391-368fdf8ab964@gmail.com> (raw)
In-Reply-To: <d7bcc8c2-f531-91f5-47e6-d18d8a99c1e1@fb.com>



On 12/16/19 3:08 PM, Alexei Starovoitov wrote:
> On 12/16/19 11:14 AM, Martin Lau wrote:
>> At least for bpf_dctcp.c, I did not expect it could be that close to tcp_dctcp.c
>> when I just started converted it.  tcp_cubic/bpf_cubic still has some TBD
>> on jiffies/msec.
>>
>> Agree that it is beneficial to have one copy.   It is likely
>> I need to make some changes on the tcp_*.c side also.  Hence, I prefer
>> to give it a try in a separate series, e.g. revert the kernel side
>> changes will be easier.
> 
> I've looked at bpf_cubic.c and bpf_dctcp.c as examples of what this
> patch set can do. They're selftests of the feature.
> What's the value of keeping them in sync with real kernel cc-s?
> I think it's fine if they quickly diverge.
> The value of them as selftests is important though. Quite a bit of BTF
> and verifier logic is being tested.
> May be add a comment saying that bpf_cubic.c is like cubic, but doesn't
> have to be exactly cubic ?
> 

The reason I mentioned this is that I am currently working on a fix of Hystart
logic, which is quite broken at the moment.

(hystart_train detection triggers in cases it should not)

But yes, if we add a comment warning potential users, this should be fine.

  reply	other threads:[~2019-12-17  0:34 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-14  0:47 [PATCH bpf-next 00/13] Introduce BPF STRUCT_OPS Martin KaFai Lau
2019-12-14  0:47 ` [PATCH bpf-next 01/13] bpf: Save PTR_TO_BTF_ID register state when spilling to stack Martin KaFai Lau
2019-12-16 19:48   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 02/13] bpf: Avoid storing modifier to info->btf_id Martin KaFai Lau
2019-12-16 21:34   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 03/13] bpf: Add enum support to btf_ctx_access() Martin KaFai Lau
2019-12-16 21:36   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 04/13] bpf: Support bitfield read access in btf_struct_access Martin KaFai Lau
2019-12-16 22:05   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 05/13] bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS Martin KaFai Lau
2019-12-17  6:14   ` Yonghong Song
2019-12-18 16:41     ` Martin Lau
2019-12-14  0:47 ` [PATCH bpf-next 06/13] bpf: Introduce BPF_MAP_TYPE_STRUCT_OPS Martin KaFai Lau
2019-12-17  7:48   ` [Potential Spoof] " Yonghong Song
2019-12-20  7:22     ` Martin Lau
2019-12-20 16:52       ` Martin Lau
2019-12-20 18:41         ` Andrii Nakryiko
2019-12-14  0:47 ` [PATCH bpf-next 07/13] bpf: tcp: Support tcp_congestion_ops in bpf Martin KaFai Lau
2019-12-17 17:36   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 08/13] bpf: Add BPF_FUNC_tcp_send_ack helper Martin KaFai Lau
2019-12-17 17:41   ` Yonghong Song
2019-12-14  0:47 ` [PATCH bpf-next 09/13] bpf: Add BPF_FUNC_jiffies Martin KaFai Lau
2019-12-14  1:59   ` Eric Dumazet
2019-12-14 19:25     ` Neal Cardwell
2019-12-16 19:30       ` Martin Lau
2019-12-17  8:26       ` Jakub Sitnicki
2019-12-17 18:22         ` Martin Lau
2019-12-17 21:04           ` Eric Dumazet
2019-12-18  9:03           ` Jakub Sitnicki
2019-12-16 19:14     ` Martin Lau
2019-12-16 19:33       ` Eric Dumazet
2019-12-16 21:17         ` Martin Lau
2019-12-16 23:08       ` Alexei Starovoitov
2019-12-17  0:34         ` Eric Dumazet [this message]
2019-12-14  0:48 ` [PATCH bpf-next 10/13] bpf: Synch uapi bpf.h to tools/ Martin KaFai Lau
2019-12-14  0:48 ` [PATCH bpf-next 11/13] bpf: libbpf: Add STRUCT_OPS support Martin KaFai Lau
2019-12-18  3:07   ` Andrii Nakryiko
2019-12-18  7:03     ` Martin Lau
2019-12-18  7:20       ` Martin Lau
2019-12-18 16:36         ` Andrii Nakryiko
2019-12-18 16:34       ` Andrii Nakryiko
2019-12-18 17:33         ` Martin Lau
2019-12-18 18:14           ` Andrii Nakryiko
2019-12-18 20:19             ` Martin Lau
2019-12-19  8:53             ` Toke Høiland-Jørgensen
2019-12-19 20:49               ` Andrii Nakryiko
2019-12-20 10:16                 ` Toke Høiland-Jørgensen
2019-12-20 17:34                   ` Andrii Nakryiko
2019-12-14  0:48 ` [PATCH bpf-next 12/13] bpf: Add bpf_dctcp example Martin KaFai Lau
2019-12-14  0:48 ` [PATCH bpf-next 13/13] bpf: Add bpf_cubic example Martin KaFai Lau
2019-12-14  2:26 ` [PATCH bpf-next 00/13] Introduce BPF STRUCT_OPS Eric Dumazet

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