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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48febe6b9efsm88903165e9.5.2026.05.17.07.10.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 17 May 2026 07:10:43 -0700 (PDT) Date: Sun, 17 May 2026 15:10:41 +0100 From: David Laight To: Qais Yousef Cc: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Juri Lelli , Steven Rostedt , John Stultz , Thomas Gleixner , Frederic Weisbecker , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] sched/tick: Decouple sched_tick() from HZ Message-ID: <20260517151041.10a9a355@pumpkin> In-Reply-To: <20260517040740.444729-1-qyousef@layalina.io> References: <20260517040740.444729-1-qyousef@layalina.io> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 17 May 2026 05:07:37 +0100 Qais Yousef wrote: > Previous attempt to make HZ 1000 the default [1] to help with scheduler > responsiveness didn't get merged. But maybe for the best, as I think this idea > of decoupling sched_tick() from HZ makes more sense. We shouldn't need to make > a choice between how often timers should trigger vs how often should the > scheduler update its stats/take decisions. Have you also looked a decoupling HZ/jiffies from the timer interrupt rate? It ought to be reasonable set HZ to 1000 and to do 'jiffies += 4' when the timer interrupts 250 times a second. I'd expect most code to handle that fine. I know one architecture (forgotten which) traditionally used a 1024Hz clock, and some very old ones 60Hz; but I don't think Linux supports either. -- David