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Fri, 02 Oct 2026 00:09:03 -0700 (PDT) Received: from gmonaco-thinkpadt14gen3.rmtit.csb ([185.168.96.228]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48b38103856sm3849229f8f.25.2026.10.02.00.09.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2026 00:09:02 -0700 (PDT) Message-ID: Subject: Re: [PATCH v2 01/15] sched: Add task enqueue/dequeue trace points From: Gabriele Monaco To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Ingo Molnar , Nam Cao , K Prateek Nayak , Alexei Starovoitov , Wen Yang , Tobias Schaffner , Viktor Malik Date: Fri, 02 Oct 2026 09:09:01 +0200 In-Reply-To: <20261001154934.GT88198@noisy.programming.kicks-ass.net> References: <20261001152042.124445-1-gmonaco@redhat.com> <20261001152042.124445-2-gmonaco@redhat.com> <20261001154934.GT88198@noisy.programming.kicks-ass.net> Autocrypt: addr=gmonaco@redhat.com; prefer-encrypt=mutual; keydata=mDMEZuK5YxYJKwYBBAHaRw8BAQdAmJ3dM9Sz6/Hodu33Qrf8QH2bNeNbOikqYtxWFLVm0 1a0JEdhYnJpZWxlIE1vbmFjbyA8Z21vbmFjb0BrZXJuZWwub3JnPoiZBBMWCgBBFiEEysoR+AuB3R Zwp6j270psSVh4TfIFAmjKX2MCGwMFCQWjmoAFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgk Q70psSVh4TfIQuAD+JulczTN6l7oJjyroySU55Fbjdvo52xiYYlMjPG7dCTsBAMFI7dSL5zg98I+8 cXY1J7kyNsY6/dcipqBM4RMaxXsOtCRHYWJyaWVsZSBNb25hY28gPGdtb25hY29AcmVkaGF0LmNvb T6InAQTFgoARAIbAwUJBaOagAULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgBYhBMrKEfgLgd0WcK eo9u9KbElYeE3yBQJoymCyAhkBAAoJEO9KbElYeE3yjX4BAJ/ETNnlHn8OjZPT77xGmal9kbT1bC1 7DfrYVISWV2Y1AP9HdAMhWNAvtCtN2S1beYjNybuK6IzWYcFfeOV+OBWRDQ== User-Agent: Evolution 3.60.2 (3.60.2-2.fc44) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: KRkd8GxiW3wqkJrFeucSTfB7QBK3dnTNAAYky0SNtRI_1790924944 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2026-10-01 at 17:49 +0200, Peter Zijlstra wrote: > On Thu, Oct 01, 2026 at 05:20:28PM +0200, Gabriele Monaco wrote: > > From: Nam Cao > >=20 > > Add trace points into enqueue_task() and dequeue_task(). > >=20 > > Signed-off-by: Nam Cao > > Suggested-by: Peter Zijlstra >=20 > Obviously I don't remember anything at all. But also, you 'forgot' to > send me the rest of the patches which might hold a clue. As is I'm > clueless as to why we want this, since the Changelog also offers none. Right.. This commit is part of [1], but borrowed from [2], which is actually more interesting to understand why I need those tracepoints. [2] contains 3 other RV deadline monitors, I should have at least CC'd you = in [3] and [4].. Essentially the enqueue and dequeue tracepoints are used to: * model the event from dl_server idle to ready (a new fair task is availab= le) * understand when a task is moved to and from another scheduler runqueue Thanks, Gabriele [1] - https://lore.kernel.org/lkml/20261001152042.124445-1-gmonaco@redhat.c= om [2] - https://lore.kernel.org/lkml/20260929124908.177676-1-gmonaco@redhat.c= om [3] - https://lore.kernel.org/lkml/20260929124908.177676-8-gmonaco@redhat.c= om [4] - https://lore.kernel.org/lkml/20260929124908.177676-9-gmonaco@redhat.c= om