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Fri, 04 Sep 2026 16:34:01 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Fri, 04 Sep 2026 16:34:00 -0700 Message-Id: Cc: "Gabriele Monaco" , "Nam Cao" , "LKML" , "linux-trace-kernel" , "bpf" , "Wen Yang" , "Tobias Schaffner" , "Viktor Malik" , "Linus Torvalds" Subject: Re: [RFC PATCH 00/20] rv: Add support for BPF monitors From: "Alexei Starovoitov" To: "Steven Rostedt" X-Mailer: aerc References: <20260831090524.106845-1-gmonaco@redhat.com> <87se3sakgi.fsf@yellow.woof> <20260903090211.50d15220@gandalf.local.home> <20260904074317.01b2c0e1@robin> <20260904123108.1fa1d815@gandalf.local.home> <20260904132421.111c0279@gandalf.local.home> In-Reply-To: <20260904132421.111c0279@gandalf.local.home> On Fri Sep 4, 2026 at 10:24 AM PDT, Steven Rostedt wrote: > On Fri, 4 Sep 2026 12:31:08 -0400 > Steven Rostedt wrote: > >> In the beginning, Daniel Bristot looked into doing this with BPF and fou= nd >> issues with it. I do not recall what they were and unfortunately Daniel = is >> no longer around to explain it. Maybe Gabriele knows what they were. > > IIRC, Daniel even told me there was a competing effort within Red Hat to > implement the same functionality using only BPF. That effort never > materialized and everything went toward the RV code Daniel was working on= . bpf in 2022 was surely less capable then it is today. It took us 2 years of bpf core development to statisfy sched-ext demands and we're still adding new features for sched-ext needs. If you're trully willing to remove 90% of kernel/trace/rv/ and refactor it into tiny shim where all of the core pieces are bpf driven we can certainly work together (like we did with sched-ext) and add whatever is missing on bpf side. Then all existing monitors will become bpf programs= . But adding bpf as another 'monitor', sorry but hard NO. If hardcoded monitors was a mistake then admit it and fix it by deleting it= , if it's not a mistake then keep adding hardcoded monitors.