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Wed, 16 Jul 2025 07:07:19 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHMGLnEBjMAuOVnncL9pST+yEzGrrXmlW5O5822Ksx735cKfIpDH13N4slQf+5+QbAygFGD/Q== X-Received: by 2002:a05:6000:2b0c:b0:3a3:70ab:b274 with SMTP id ffacd0b85a97d-3b609524369mr4320828f8f.12.1752674838921; Wed, 16 Jul 2025 07:07:18 -0700 (PDT) Received: from gmonaco-thinkpadt14gen3.rmtit.csb ([185.107.56.42]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4562e83e1d6sm21934665e9.35.2025.07.16.07.07.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jul 2025 07:07:18 -0700 (PDT) Message-ID: Subject: Re: [PATCH v3 12/17] sched: Adapt sched tracepoints for RV task model From: Gabriele Monaco To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Steven Rostedt , Masami Hiramatsu , linux-trace-kernel@vger.kernel.org, Nam Cao , Tomas Glozar , Juri Lelli , Clark Williams , John Kacur Date: Wed, 16 Jul 2025 16:07:16 +0200 In-Reply-To: <20250716134513.GB905792@noisy.programming.kicks-ass.net> References: <20250715071434.22508-1-gmonaco@redhat.com> <20250715071434.22508-13-gmonaco@redhat.com> <20250716123832.GW1613200@noisy.programming.kicks-ass.net> <122cfd4ba6b0805e91ff09526d5d159ff3871964.camel@redhat.com> <20250716134513.GB905792@noisy.programming.kicks-ass.net> Autocrypt: addr=gmonaco@redhat.com; prefer-encrypt=mutual; keydata=mDMEZuK5YxYJKwYBBAHaRw8BAQdAmJ3dM9Sz6/Hodu33Qrf8QH2bNeNbOikqYtxWFLVm0 1a0JEdhYnJpZWxlIE1vbmFjbyA8Z21vbmFjb0ByZWRoYXQuY29tPoiZBBMWCgBBFiEEysoR+AuB3R Zwp6j270psSVh4TfIFAmbiuWMCGwMFCQWjmoAFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgk Q70psSVh4TfJzZgD/TXjnqCyqaZH/Y2w+YVbvm93WX2eqBqiVZ6VEjTuGNs8A/iPrKbzdWC7AicnK xyhmqeUWOzFx5P43S1E1dhsrLWgP User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) 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: 8BqI8RZf7UfbIa6mfSQUKcdtj9ws79lWUt9yFt3c-l0_1752674839 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2025-07-16 at 15:45 +0200, Peter Zijlstra wrote: >=20 > I'm not sure I understand the importance of IRQ state when describing > task transitions. >=20 > You know both: >=20 > =C2=A0- schedule() invocations for any one task are in-order; > =C2=A0- schedule() invocations for any one CPU are in-order. >=20 It's to describe latencies, which is the original purpose of the scheduler model: if the event supposed to wake up an RT task occurs with interrupts disabled while scheduling, we'd need to wait for that run to complete. Now to be fair, it doesn't really matter whether that call to __schedule switches or not, but always having a switch event simplifies things while modelling. I can rearrange models like sts (added in this series) not to expect that. Thanks, Gabriele