From: jim.cromie@gmail.com
To: Navin P <navinp0304@gmail.com>
Cc: kernelnewbies <kernelnewbies@kernelnewbies.org>
Subject: Re: pid start time and new display field in proc pid stat
Date: Thu, 25 Mar 2021 09:20:59 -0600 [thread overview]
Message-ID: <CAJfuBxx9E5SxQ6N7eD+4khVE=0fLPxCM6o0ifNVP0ira8Z9QCQ@mail.gmail.com> (raw)
In-Reply-To: <CALO2Tq+j3LPPvfaBiph4nXmOwQW9kKGMPy7NgkQbLGBDxwEt_Q@mail.gmail.com>
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On Thu, Mar 25, 2021 at 6:53 AM Navin P <navinp0304@gmail.com> wrote:
> Hi,
>
> As of 5.11 kernel (pid,pid_start_time) is not unique /monotonic even
> though the underlying counters are .
> I chose start_boottime because i wanted the counter to increase
> during suspend as well.
>
> 1. Is there any case where task->start_boottime or
> ktime_get_boottime_ns doesn't become monotonic i.e increasing ?
>
> 2. If start_boottime is not monotonic which counter to use ?
>
> 3. If i create a new field in task_struct , then i can use a
> atomic_add_return(1,&v) to fill in the task->new_field. Will this also
> work ?
>
>
Its my understanding that task-struct is a highly "contended" resource.
its a basic element, its size matters
everybody wants a bit/byte for something special,
conflicts ensue (or could).
nobody gets them without a real good reason.
I dont know what youre trying to achieve, but i suspect that
youll need to find a more subtle way of doing it.
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next prev parent reply other threads:[~2021-03-25 15:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 12:53 pid start time and new display field in proc pid stat Navin P
2021-03-25 15:20 ` jim.cromie [this message]
2021-03-26 3:01 ` Navin P
2021-04-01 14:50 ` pid start time and new display field in proc pid stat [ race in task->start_boottime ,start_time] Navin P
2021-04-03 3:21 ` pid start time and new display field in proc pid stat [ race in task->start_boottime , start_time] Valdis Klētnieks
2021-04-03 8:47 ` pid start time and new display field in proc pid stat [ race in task->start_boottime ,start_time] Navin P
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