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Mon, 12 Oct 2026 04:58:28 -0700 (PDT) Received: from gmonaco-thinkpadt14gen3.rmtit.csb ([195.174.135.130]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48db94e33d2sm20228336f8f.9.2026.10.12.04.58.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Oct 2026 04:58:28 -0700 (PDT) Message-ID: <3eb0948c9ca67f64b3b311f823cd0f7628033c68.camel@redhat.com> Subject: Re: [PATCH v7 00/14] rv: Add task latency over budget RV monitor From: Gabriele Monaco To: wen.yang@linux.dev Cc: Nam Cao , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 12 Oct 2026 13:58:27 +0200 In-Reply-To: References: Autocrypt: addr=gmonaco@redhat.com; prefer-encrypt=mutual; keydata=mDMEZuK5YxYJKwYBBAHaRw8BAQdAmJ3dM9Sz6/Hodu33Qrf8QH2bNeNbOikqYtxWFLVm0 1a0JEdhYnJpZWxlIE1vbmFjbyA8Z21vbmFjb0BrZXJuZWwub3JnPoiZBBMWCgBBFiEEysoR+AuB3R Zwp6j270psSVh4TfIFAmjKX2MCGwMFCQWjmoAFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgk Q70psSVh4TfIQuAD+JulczTN6l7oJjyroySU55Fbjdvo52xiYYlMjPG7dCTsBAMFI7dSL5zg98I+8 cXY1J7kyNsY6/dcipqBM4RMaxXsOtCRHYWJyaWVsZSBNb25hY28gPGdtb25hY29AcmVkaGF0LmNvb T6InAQTFgoARAIbAwUJBaOagAULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgBYhBMrKEfgLgd0WcK eo9u9KbElYeE3yBQJoymCyAhkBAAoJEO9KbElYeE3yjX4BAJ/ETNnlHn8OjZPT77xGmal9kbT1bC1 7DfrYVISWV2Y1AP9HdAMhWNAvtCtN2S1beYjNybuK6IzWYcFfeOV+OBWRDQ== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-2.fc44) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2026-10-12 at 03:39 +0800, wen.yang@linux.dev wrote: > From: Wen Yang >=20 > This series introduces tlob (task latency over budget), a per-task > hybrid automaton RV monitor that measures elapsed wall-clock time across > a user-delimited code section and emits an error when the elapsed time > exceeds a configurable budget. Hi Wen, there's been a conversation at the LPC conference about completely migratin= g RV to BPF. While we aren't sure of its feasibility yet, and it will take time, it's something to keep in mind for new contributions. First of all, would dropping RV in-kernel support negatively affect your cu= rrent workflow? About this series, completely converting it to BPF isn't trivial, I can kee= p on reviewing it and we could upstream it in-kernel, then convert it later (tog= ether with the work with other HA). But I'd prioritise not affecting the in-kernel implementation much to keep = it on par with the BPF one. I'd first like to focus on what should the rv userspace tool support for a monitor like yours to be useful. You'd have all reporting as stdout (or any= BPF reactor you'd want to write), then we should probably support some way to s= et the uprobe location and threshold before loading. Would you really need dynamic uprobe addition? What do you think? Thanks, Gabriele