From: Jan Kiszka <jan.kiszka@siemens.com>
To: Leandro Bucci <guestleandro11@gmail.com>, xenomai <xenomai@xenomai.org>
Subject: Re: Execution time
Date: Mon, 8 Mar 2021 11:23:33 +0100 [thread overview]
Message-ID: <acf6f25c-0b03-35fd-cba0-6b2727daae70@siemens.com> (raw)
In-Reply-To: <CAFZ-hKgcskeJnaBe6+_qAZQ6TQQhyVnShHXwaE==ScSVJLtU_w@mail.gmail.com>
On 03.03.21 15:45, Leandro Bucci via Xenomai wrote:
> Hi, I noticed a very strange but also interesting fact. When a certain
> periodic task is executed, if the period is small (for example 0.5ms) I
> have that the execution times are more or less constant (about 5 micro
> seconds). If, on the other hand, the period of the same task is larger (for
> example 10ms), the execution times are less predictable and range from 5
> micro seconds to 15 micro seconds.
>
> How is this possible? I am using a raspberry Pi3 and the task is running on
> a core dedicated to xenomai.
In general, you can see cache "temperature" effects when reducing the
period of a task: The more frequently it runs, the hotter the cache will
be and the less likely it is that relevant content for that task has be
evicted. But all that depends on many factors, the non-rt load, the load
of the task itself, the caching system etc.
Jan
--
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2021-03-08 10:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 14:45 Execution time Leandro Bucci
2021-03-08 10:23 ` Jan Kiszka [this message]
2021-03-08 10:35 ` Leandro Bucci
-- strict thread matches above, loose matches on Subject: below --
2021-02-16 11:34 Leandro Bucci
2021-02-16 14:03 ` Per Oberg
2021-02-16 14:24 ` Leandro Bucci
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