linux-kernel - Re: [PATCH v2] timers: Recalculate next timer interrupt only when necessary

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Date:   Thu, 8 Jul 2021 14:43:01 +0800
From:   He Zhe <zhe.he@...driver.com>
To:     frederic@...nel.org
Cc:     anna-maria@...utronix.de, linux-kernel@...r.kernel.org,
        tglx@...utronix.de
Subject: Re: [PATCH v2] timers: Recalculate next timer interrupt only when
 necessary

Hi,

Ever since this commit merged in, when nohz_full enabled, the counts of arch_timer interrupt on arm64 arches keep increasing on cores that have been isolated. This can be reproduced on several arm64 boards. After reverting the commit, the counts would stop increasing after boot. my .config is attached.

root@...uarm64:~# uname -a
Linux qemuarm64 5.13.0 #1 SMP PREEMPT Mon Jul 5 07:11:27 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
root@...uarm64:~# cat /proc/cmdline
root=/dev/vda rw  mem=2048M ip=dhcp console=ttyAMA0 console=hvc0  earlyprintk isolcpus=1-5 nohz_full=1-5 rcu_nocbs=1-5
root@...uarm64:~# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3       CPU4       CPU5      
 11:      12396        326        325        323        320        321     GIC-0  27 Level     arch_timer


Zhe

View attachment "config-arm64-intterrupt" of type "text/plain" (107808 bytes)