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From: Jiri Benc <jbenc@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: "David Ahern" <dsahern@gmail.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
	"Hangbin Liu" <haliu@redhat.com>,
	"Stephen Hemminger" <stephen@networkplumber.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"David Miller" <davem@davemloft.net>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>
Subject: Re: [PATCHv3 iproute2-next 0/5] iproute2: add libbpf support
Date: Fri, 6 Nov 2020 10:00:07 +0100	[thread overview]
Message-ID: <20201106100007.10049857@redhat.com> (raw)
In-Reply-To: <CAEf4BzbQz5ZqoB3TEtM-4e=Ndx9WCGN16Be8-JoK+mvUyAGC3w@mail.gmail.com>

On Thu, 5 Nov 2020 12:45:39 -0800, Andrii Nakryiko wrote:
> That's not true. If you need new functionality like BTF, CO-RE,
> function-by-function verification, etc., then yes, you have to update
> kernel, compiler, libbpf, sometimes pahole. But if you have an BPF
> application that doesn't use and need any of the newer features, it
> will keep working just fine with the old kernel, old libbpf, and old
> compiler.

I'm fine with this.

It doesn't work that well in practice, we've found ourselves chasing
problems caused by llvm update (problems for older bpf programs, not
new ones), problems on non-x86_64 caused by kernel updates, etc. It can
be attributed to living on the edge and it should stabilize over time,
hopefully. But it's still what the users are experiencing and it's
probably what David is referring to. I expect it to smooth itself over
time.

Add to that the fact that something that is in fact a new feature is
perceived as a bug fix by some users. For example, a perfectly valid
and simple C program, not using anything shiny but a basic simple loop,
compiles just fine but is rejected by the kernel. A newer kernel and a
newer compiler and a newer libbpf and a newer pahole will cause the
same program to be accepted. Now, the user does not see that for this,
a new load of BTF functionality had to be added and all those mentioned
projects enhanced with substantial code. All they see is their simple
hello world test program did not work and now it does.

I'm not saying I have a solution nor I'm saying you should do something
about it. Just trying to explain the perception.

 Jiri


  reply	other threads:[~2020-11-06  9:00 UTC|newest]

Thread overview: 167+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-23  3:38 [PATCH iproute2-next 0/5] iproute2: add libbpf support Hangbin Liu
2020-10-23  3:38 ` [PATCH iproute2-next 1/5] configure: add check_libbpf() for later " Hangbin Liu
2020-10-23  3:38 ` [PATCH iproute2-next 2/5] lib: rename bpf.c to bpf_legacy.c Hangbin Liu
2020-10-23  3:38 ` [PATCH iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-10-23 14:34   ` David Ahern
2020-10-25 15:13     ` Toke Høiland-Jørgensen
2020-10-25 22:12       ` David Ahern
2020-10-26  8:56         ` Hangbin Liu
2020-10-26 15:15           ` David Ahern
2020-10-27  2:58             ` Hangbin Liu
2020-10-24  0:21   ` Andrii Nakryiko
2020-10-25 15:11     ` Toke Høiland-Jørgensen
2020-10-26  8:10     ` Hangbin Liu
2020-10-23  3:38 ` [PATCH iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-10-23  3:38 ` [PATCH iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-10-28 13:25 ` [PATCHv2 iproute2-next 0/5] iproute2: add libbpf support Hangbin Liu
2020-10-28 13:25   ` [PATCHv2 iproute2-next 1/5] configure: add check_libbpf() for later " Hangbin Liu
2020-10-28 13:25   ` [PATCHv2 iproute2-next 2/5] lib: rename bpf.c to bpf_legacy.c Hangbin Liu
2020-10-28 13:25   ` [PATCHv2 iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-10-28 13:25   ` [PATCHv2 iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-10-28 13:25   ` [PATCHv2 iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-10-28 21:17   ` [PATCHv2 iproute2-next 0/5] iproute2: add libbpf support Alexei Starovoitov
2020-10-28 23:02   ` David Ahern
2020-10-29  2:06     ` Hangbin Liu
2020-10-29  2:20       ` David Ahern
2020-10-29  2:45         ` Hangbin Liu
2020-10-29  3:00           ` David Ahern
2020-10-29  3:17             ` Hangbin Liu
2020-10-29 10:26             ` Hangbin Liu
2020-10-29 10:51               ` Toke Høiland-Jørgensen
2020-10-29  2:27       ` Andrii Nakryiko
2020-10-29  2:33         ` David Ahern
2020-10-29  2:46           ` Andrii Nakryiko
2020-10-29  2:34         ` Stephen Hemminger
2020-10-29  2:50           ` Andrii Nakryiko
2020-10-29 11:38             ` Jesper Dangaard Brouer
2020-10-29 20:30               ` Andrii Nakryiko
2020-10-29  2:33       ` Stephen Hemminger
2020-10-29 15:11   ` [PATCHv3 " Hangbin Liu
2020-10-29 15:11     ` [PATCHv3 iproute2-next 1/5] configure: add check_libbpf() for later " Hangbin Liu
2020-10-29 15:26       ` Toke Høiland-Jørgensen
2020-11-02 15:37       ` David Ahern
2020-11-03  5:54         ` Hangbin Liu
2020-11-03 17:32           ` David Ahern
2020-11-04  8:51             ` Hangbin Liu
2020-11-04 11:09               ` Toke Høiland-Jørgensen
2020-11-04 11:40                 ` Hangbin Liu
2020-10-29 15:11     ` [PATCHv3 iproute2-next 2/5] lib: rename bpf.c to bpf_legacy.c Hangbin Liu
2020-10-29 15:11     ` [PATCHv3 iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-11-02 15:41       ` David Ahern
2020-11-03  5:48         ` Hangbin Liu
2020-11-03 17:19           ` David Ahern
2020-11-04  8:22         ` Hangbin Liu
2020-11-05  2:33           ` David Ahern
2020-11-05  7:51             ` Hangbin Liu
2020-11-05 15:25               ` David Ahern
2020-11-05 15:57                 ` Toke Høiland-Jørgensen
2020-11-05 16:02                   ` David Ahern
2020-11-06  0:56                     ` Hangbin Liu
2020-11-06  0:41                 ` Hangbin Liu
2020-10-29 15:11     ` [PATCHv3 iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-10-29 15:11     ` [PATCHv3 iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-11-02 15:47     ` [PATCHv3 iproute2-next 0/5] iproute2: add libbpf support David Ahern
2020-11-03  6:58       ` Andrii Nakryiko
2020-11-03  8:42         ` Jiri Benc
2020-11-03 17:45           ` David Ahern
2020-11-03 17:48           ` Alexei Starovoitov
2020-11-03  8:46         ` Daniel Borkmann
2020-11-03 17:35           ` David Ahern
2020-11-03 17:47             ` Alexei Starovoitov
2020-11-03 18:23               ` Stephen Hemminger
2020-11-03 22:32               ` David Ahern
2020-11-03 22:55                 ` Alexei Starovoitov
2020-11-04  1:40                   ` David Ahern
2020-11-04  2:45                     ` Alexei Starovoitov
2020-11-04  9:28                       ` Jiri Benc
2020-11-05  2:39                         ` David Ahern
2020-11-04  2:17                   ` Hangbin Liu
2020-11-04  3:11                     ` Alexei Starovoitov
2020-11-04 10:01                       ` Jiri Benc
2020-11-04 10:21                       ` Daniel Borkmann
2020-11-04 11:20                         ` Toke Høiland-Jørgensen
2020-11-04 13:12                           ` Daniel Borkmann
2020-11-04 19:17                             ` Jakub Kicinski
2020-11-04 20:43                               ` Andrii Nakryiko
2020-11-04 22:24                                 ` Toke Høiland-Jørgensen
2020-11-05 20:14                                   ` Andrii Nakryiko
2020-11-05  3:48                                 ` David Ahern
2020-11-05 20:53                                   ` Andrii Nakryiko
2020-11-05  3:19                         ` David Ahern
2020-11-05 14:05                           ` Jamal Hadi Salim
2020-11-05 21:01                             ` Andrii Nakryiko
2020-11-06 15:27                               ` Jamal Hadi Salim
2020-11-06 21:25                                 ` Andrii Nakryiko
2020-11-10 12:47                             ` Edward Cree
2020-11-11  0:53                               ` Alexei Starovoitov
2020-11-11 11:31                                 ` Edward Cree
2020-11-11 18:08                                   ` Alexei Starovoitov
2020-11-05 20:45                           ` Andrii Nakryiko
2020-11-06  9:00                             ` Jiri Benc [this message]
2020-11-06 21:07                               ` Andrii Nakryiko
2020-11-04 21:15                       ` Edward Cree
2020-11-04 22:10                         ` Alexei Starovoitov
2020-11-04 22:35                           ` Toke Høiland-Jørgensen
2020-11-04 23:05                           ` Edward Cree
2020-11-05 20:19                             ` Andrii Nakryiko
2020-11-06  8:44                               ` Jiri Benc
2020-11-06 20:57                                 ` Andrii Nakryiko
2020-11-06 21:04                                   ` Alexei Starovoitov
2020-11-06 23:25                                     ` Stephen Hemminger
2020-11-06 23:30                                       ` Andrii Nakryiko
2020-11-07  0:41                                         ` Stephen Hemminger
2020-11-07  1:07                                           ` Andrii Nakryiko
2020-11-06 23:38                                       ` David Ahern
2020-11-09  1:45                                         ` Alexei Starovoitov
2020-11-10  4:09                                           ` David Ahern
2020-11-11  0:47                                             ` Alexei Starovoitov
2020-11-11 11:02                                               ` Toke Høiland-Jørgensen
2020-11-11 15:06                                                 ` Daniel Borkmann
2020-11-11 16:33                                                   ` David Ahern
2020-11-12 22:36                                                   ` Toke Høiland-Jørgensen
2020-11-12 23:20                                                     ` Daniel Borkmann
2020-11-13  0:04                                                       ` Stephen Hemminger
2020-11-13  0:40                                                         ` Alexei Starovoitov
2020-11-13  3:55                                                       ` David Ahern
2020-11-09  7:07     ` [PATCHv4 " Hangbin Liu
2020-11-09  7:07       ` [PATCHv4 iproute2-next 1/5] configure: add check_libbpf() for later " Hangbin Liu
2020-11-14  3:26         ` David Ahern
2020-11-16  4:30           ` Hangbin Liu
2020-11-16  4:33             ` David Ahern
2020-11-09  7:07       ` [PATCHv4 iproute2-next 2/5] lib: rename bpf.c to bpf_legacy.c Hangbin Liu
2020-11-14  3:24         ` David Ahern
2020-11-16  3:55           ` Hangbin Liu
2020-11-09  7:08       ` [PATCHv4 iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-11-09  7:08       ` [PATCHv4 iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-11-09  7:08       ` [PATCHv4 iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-11-16  6:53       ` [PATCHv5 iproute2-next 0/5] iproute2: add libbpf support Hangbin Liu
2020-11-16  6:53         ` [PATCHv5 iproute2-next 1/5] configure: add check_libbpf() for later " Hangbin Liu
2020-11-16  6:53         ` [PATCHv5 iproute2-next 2/5] lib: rename bpf.c to bpf_legacy.c Hangbin Liu
2020-11-16  6:53         ` [PATCHv5 iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-11-16  6:53         ` [PATCHv5 iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-11-16  6:53         ` [PATCHv5 iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-11-16  7:19         ` [PATCHv5 iproute2-next 0/5] iproute2: add libbpf support Alexei Starovoitov
2020-11-16 14:54           ` Jesper Dangaard Brouer
2020-11-16 23:29             ` Toke Høiland-Jørgensen
2020-11-17  2:37             ` Alexei Starovoitov
2020-11-17  3:19               ` Hangbin Liu
2020-11-17 18:27                 ` Alexei Starovoitov
2020-11-17 11:56               ` Edward Cree
2020-11-17  3:38             ` David Ahern
2020-11-17 18:19               ` Alexei Starovoitov
2020-11-16 16:45           ` Stephen Hemminger
2020-11-23 13:11         ` [PATCHv6 " Hangbin Liu
2020-11-23 13:11           ` [PATCHv6 iproute2-next 1/5] iproute2: add check_libbpf() and get_libbpf_version() Hangbin Liu
2020-11-23 13:11           ` [PATCHv6 iproute2-next 2/5] lib: make ipvrf able to use libbpf and fix function name conflicts Hangbin Liu
2020-11-23 13:11           ` [PATCHv6 iproute2-next 3/5] lib: add libbpf support Hangbin Liu
2020-11-23 13:12           ` [PATCHv6 iproute2-next 4/5] examples/bpf: move struct bpf_elf_map defined maps to legacy folder Hangbin Liu
2020-11-23 13:12           ` [PATCHv6 iproute2-next 5/5] examples/bpf: add bpf examples with BTF defined maps Hangbin Liu
2020-11-25  5:28           ` [PATCHv6 iproute2-next 0/5] iproute2: add libbpf support David Ahern
2020-11-25  5:30           ` patchwork-bot+netdevbpf
2020-11-29  6:16 ` [PATCH " Stephen Hemminger
2020-11-29  6:22   ` Greg KH
2020-11-30 11:39     ` Michal Kubecek
2020-11-29 17:33   ` Alexei Starovoitov
2020-11-29 19:41   ` David Ahern
2020-11-30 11:04     ` Toke Høiland-Jørgensen
2020-12-01 14:22     ` Jesper Dangaard Brouer

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