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bh=5OhWPAu4aphIzD7xlFqULoTdQ1d9FLpBhL4JzORAtrE=; b=pzwTHOiw0eZL5YDmeqk51vz9SLKgEg85QZWTqMPS1jHY0dwDmSWRFIl4awVJf1+3JTqD1c EGbeNjBzmXsaL/ZBpZkb85ozSbbD0JPbF4NwdRakdpHOeDrP8LImCCi1Uqvieo15WRkXVJ UioM7O2jzD6wS8TQx+k5r4O46ML0VN+lhZZ8lV/Qg84z5w0HE0fSYIVmCHODc9fmmdwRF4 cW/8zakoTdOfZTue0x0Paz0+yDG1C/rUfQJkcUR+UXEpuezhP6gyKk0YiotiWEdSdUpJn7 9QyXU6SJX7aYAQ8rIuNt0Mf5/s2b4pXAMvUHzxsn2SVw/Q9Ic0QJlCdfgu7CEg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1738850035; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5OhWPAu4aphIzD7xlFqULoTdQ1d9FLpBhL4JzORAtrE=; b=iTyIeh7Njzn/4TjYMIJNO4dZZ06HQrrqMMFtJMLkWxziMGXg5Pcp1QHiud1ezdWMm5fhIE oUSv4/bv/q0c5iDw== From: Sebastian Andrzej Siewior To: Peter Zijlstra Cc: Steven Rostedt , Joel Fernandes , Prakash Sangappa , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Thomas Gleixner , Ankur Arora , Linus Torvalds , linux-mm@kvack.org, x86@kernel.org, Andrew Morton , luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, Boris Ostrovsky , Konrad Wilk , jgross@suse.com, Andrew.Cooper3@citrix.com, Vineeth Pillai , Suleiman Souhlal , Ingo Molnar , Mathieu Desnoyers , Clark Williams , daniel.wagner@suse.com, Joseph Salisbury , broonie@gmail.com Subject: Re: [RFC][PATCH 1/2] sched: Extended scheduler time slice Message-ID: <20250206135353.i1tp4vDv@linutronix.de> References: <9DA1FAE6-A008-4785-BDF9-541457E29807@joelfernandes.org> <20250204220418.35949317@gandalf.local.home> <20250205081635.397eacb0@gandalf.local.home> <20250206083039.0916ad24@gandalf.local.home> <20250206134408.lD_POjuG@linutronix.de> <20250206134859.GP7145@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250206134859.GP7145@noisy.programming.kicks-ass.net> X-Stat-Signature: wm7wyw3hsnhdfupq7mqbpza5qpjdqasp X-Rspamd-Queue-Id: 65DCC40050 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1738850338-390284 X-HE-Meta: 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 P3bNGz4s brMJsYBPVNRUlJ5ZC8hdjQICwYrE33i20rnXFu0qo0guRHgRIdPHeHoLPM1tn17cL/6s1JD59JeZIuwryeS4zi2tM5/uoRIpPBv9vtMRyy2sB1SLofIS5a41itLcGAZYFAZFZkaw6B8DcB66n47VegZU+KnNvgXWVBZ7Nqk1dzGY7HR+u8Er8m/cezat+JyvF2+68AUIlpUUfkmTGJUg/oV4E7gtNq5mI+aHIt5cYbem2I2F8fH0H0JJAxlX3H/APIymNQ803y5LY8Qg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-02-06 14:48:59 [+0100], Peter Zijlstra wrote: > On Thu, Feb 06, 2025 at 02:44:08PM +0100, Sebastian Andrzej Siewior wrote: > > SCHED_OTHER vs SCHED_OTHER after all. But please don't delay a wakeup of > > SCHED_FIFO/ RR/ DL because of this LAZY hint. > > Thing will get delayed if interrupts are disabled or kernel has > preemption disabled too. So as long as we ensure hint crap is of equal > order, nothing cares if you do. > > If you can't tell the difference between task does hint crap in > userspace and task is in the middle of syscall, you can't tell the > difference. I can tell the difference if I see a trace where an interrupt fires, performs a wakeup and the SCHED_OTHER task remains on CPU while the task SCHED_FIFO task sits on the runqueue until a timer fires. Sebastian