From: "Li,Rongqing" <lirongqing@baidu.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: "mingo@redhat.com" <mingo@redhat.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"juri.lelli@redhat.com" <juri.lelli@redhat.com>,
"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"bsegall@google.com" <bsegall@google.com>,
"mgorman@suse.de" <mgorman@suse.de>,
"vschneid@redhat.com" <vschneid@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: 答复: [外部邮件] Re: [PATCH] sched/cputime: Fix a mostly theoretical divide by zero
Date: Tue, 17 Jun 2025 06:36:37 +0000 [thread overview]
Message-ID: <4709b236e32a41158994dae282f2be75@baidu.com> (raw)
In-Reply-To: <CAKfTPtBKm7WgwcUHcMXnH3PL3KFSniy02mb6Ag4eQ1fA3e+H3g@mail.gmail.com>
> Theoretical is the right word; If all 2^32 possible threads belong to the process,
> we can get an overflow to 0 after ~4sec run time of each thread. But then how
> long will it take to have those 2^32 threads run 4sec on a system ...
>
> It would be good to get number to show how realistic or not it could be to
> reach this value
>
>
The 2^64 ns is 584 years, if a process with 1000 busy polling threads is running in a machine with more than 1000 CPUs, the runtime will overflow about half year
Thank
-LI
prev parent reply other threads:[~2025-06-17 6:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-04 11:04 lirongqing
2025-06-16 11:46 ` 答复: " Li,Rongqing
2025-06-16 12:51 ` Vincent Guittot
2025-06-16 14:48 ` David Laight
2025-06-17 6:36 ` Li,Rongqing [this message]
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