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bh=N8TrgMR8y7z0t4Qq091mxwCJeAMw03oWCq6ybsKg5Ys=; b=RDGWtlw8A+YnbXdaAO3Q5c4eHfTcOJxPBJxo4EX03YHnaY99mjxo/LjfQdgu6QLjuKQxri U6Ev56U2iMohUuur6AmqiwhCrG3EWmKYZ/rKLhnOz17lB2VCW4Yf0j1r/n/91YSz0ugzwQ ev/zucwjk6Yg8t65d9rh3NByIqdvxHaAASBp45hacmQCY2FnvFZkTyWcD9CKgoKoyLuv18 pxOMgvaLEv/2Es/aMdB11LEOoQEPEAwZqrp/H3dObPIbvjin4OA+x7G8rw1u9ElVklSUMD IPfAXKHWsSWa3U3c7scpb1KmK7BIvCDkvGasxwIHmULv41+HxY9G7R6K7x2r7Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1710408724; 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=N8TrgMR8y7z0t4Qq091mxwCJeAMw03oWCq6ybsKg5Ys=; b=6fAbWKbp6g+P2ZRGwii8GzEO9Do+uI8Vg+JfQ9E8ZGMIIKVhXA7QjJnbymUhsOgdlwQweQ 37Ni6cZ2CbRC5eDA== To: Boqun Feng , Florian Fainelli Cc: Frederic Weisbecker , "Russell King (Oracle)" , Joel Fernandes , Anna-Maria Behnsen , Linus Torvalds , linux-kernel@vger.kernel.org, kernel-team@meta.com, paulmck@kernel.org, mingo@kernel.org, rcu@vger.kernel.org, neeraj.upadhyay@amd.com, urezki@gmail.com, qiang.zhang1211@gmail.com, bigeasy@linutronix.de, chenzhongjin@huawei.com, yangjihong1@huawei.com, rostedt@goodmis.org, Justin Chen Subject: Re: Unexplained long boot delays [Was Re: [GIT PULL] RCU changes for v6.9] In-Reply-To: References: <2fb110ed-ba04-4320-9ef0-8766c9df5578@gmail.com> <533151c9-afb5-453b-8014-9fbe7c3b26c2@gmail.com> Date: Thu, 14 Mar 2024 10:32:03 +0100 Message-ID: <87il1pma5o.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Wed, Mar 13 2024 at 23:33, Boqun Feng wrote: > but here: > > [ 221.555265] kworker/-44 0d.... 3279414us : timer_start: timer=95703ccd function=process_timeout expires=4294670586 [timeout=10] bucket_expiry=4294670587 cpu=0 idx =59 flags= > > this is a normal timer. > > [ 221.571298] rcu_sche-15 3d.... 3279417us : timer_start: timer=7e541f87 function=process_timeout expires=4294670579 [timeout=3] bucket_expiry=4294670580 cpu=3 idx= 52 flags= > [ 221.587241] -0 1d.s.. 3283405us : timer_cancel: timer=7e541f87 > [ 221.594488] -0 1..s.. 3283407us : timer_expire_entry: timer=7e541f87 function=process_timeout now=4294670580 baseclk=4294670580 > [ 221.607388] rcu_sche-15 3d.... 3283416us : timer_start: timer=7e541f87 function=process_timeout expires=4294670583 [timeout=3] bucket_expiry=4294670584 cpu=3 idx= 56 flags= > [ 221.623331] -0 1d.s.. 3287404us : timer_cancel: timer=7e541f87 > [ 221.630578] -0 1..s.. 3287405us : timer_expire_entry: timer=7e541f87 function=process_timeout now=4294670584 baseclk=4294670584 > [ 221.643475] -0 0d.s.. 162361292us : timer_cancel: timer=95703ccd > [ 221.650896] -0 0..s.. 162361292us : timer_expire_entry: timer=95703ccd function=process_timeout now=4294829657 baseclk=4294670587 > > which got fired here. > > [ 221.663967] -0 0dns.. 162361296us : timer_cancel: timer=d03eaa1d > [ 221.671388] -0 0.ns.. 162361297us : timer_expire_entry: timer=d03eaa1d function=process_timeout now=4294829657 baseclk=4294670856 > > And looks to me CPU 0 is the tick_do_timer_cpu CPU, since it's the first > one that got timers after a long wait and was doing a few catch-ups. Now > the problem is why CPU 0 didn't program its hardware timer to expire at > 4294670587? I.e. the earliest timer. That's not the problem. It's not clear whether CPU0 was the last one going idle. It doesn't look so: > [ 221.623331] -0 1d.s.. 3287404us : timer_cancel: timer=7e541f87 > [ 221.630578] -0 1..s.. 3287405us : timer_expire_entry: timer=7e541f87 function=process_timeout now=4294670584 baseclk=4294670584 The timer in question is supposed to wake up 2 ticks later, so CPU1 should have armed it. But without the migration trace points enabled this is all guess work. Thanks, tglx