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([2620:10d:c090:600::1:255e]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-31f63da5719sm17523330a91.6.2025.08.05.10.14.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Aug 2025 10:14:25 -0700 (PDT) Message-ID: Subject: Re: [PATCH v3 1/2] libbpf: Add the ability to suppress perf event enablement From: Eduard Zingerman To: Alexei Starovoitov , Ilya Leoshkevich Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Ian Rogers , Arnaldo Carvalho de Melo , bpf , "linux-perf-use." , LKML , linux-s390 , Thomas Richter , Jiri Olsa , Heiko Carstens , Vasily Gorbik , Alexander Gordeev Date: Tue, 05 Aug 2025 10:14:23 -0700 In-Reply-To: References: <20250805130346.1225535-1-iii@linux.ibm.com> <20250805130346.1225535-2-iii@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2025-08-05 at 09:45 -0700, Alexei Starovoitov wrote: > On Tue, Aug 5, 2025 at 6:04=E2=80=AFAM Ilya Leoshkevich wrote: > >=20 > > Automatically enabling a perf event after attaching a BPF prog to it is > > not always desirable. > >=20 > > Add a new no_ioctl_enable field to struct bpf_perf_event_opts. While > > introducing ioctl_enable instead would be nicer in that it would avoid > > a double negation in the implementation, it would make > > DECLARE_LIBBPF_OPTS() less efficient. > >=20 > > Suggested-by: Jiri Olsa > > Co-developed-by: Thomas Richter > > Signed-off-by: Thomas Richter > > Signed-off-by: Ilya Leoshkevich > > --- Acked-by: Eduard Zingerman [...] > > --- a/tools/lib/bpf/libbpf.h > > +++ b/tools/lib/bpf/libbpf.h > > @@ -499,9 +499,11 @@ struct bpf_perf_event_opts { > > __u64 bpf_cookie; > > /* don't use BPF link when attach BPF program */ > > bool force_ioctl_attach; > > + /* don't automatically enable the event */ > > + bool no_ioctl_enable; >=20 > The patch logic looks fine, but I feel the knob name is too > implementation oriented. > imo "dont_auto_enable" is more descriptive and easier > to reason about. >=20 > Let's wait for Eduard/Andrii reviews. This patch has to go > via bpf trees first while the latter via perf. Agree with Alexei, something like "dont_enable" should be simpler to read.