From: Michel Macena Oliveira <michel@austral-dynamics.com>
To: Daniel Wagner <wagi@monom.org>, linux-rt-users@vger.kernel.org
Subject: Re: PREEMPT_RT benchmark
Date: Thu, 11 Mar 2021 11:56:50 -0300 [thread overview]
Message-ID: <CAKkbJ-x4Er7RKhvrThtmmf-MT5uakdkc2G0ZL06i-fGsmBzmSg@mail.gmail.com> (raw)
In-Reply-To: <9be68ca5-9fec-161c-1b37-1b47c0a1d845@monom.org>
Hi Daniel,
Thanks for your answer! That was the problem!
If I understand correctly when Cyclictest writes to the
cpu_dma_latency file, the processor does not sleep and remain
full power all the time. Is there any problem writing a RT application
(not a benchmark one) with this trick?
Could it cause any harm to the system?
My idea is to develop a RT application in which I have a scheduled
thread to compute and deliver results in a given time or interval.
Michel
Em qui., 11 de mar. de 2021 às 09:27, Daniel Wagner <wagi@monom.org> escreveu:
>
> Hi Michel,
>
> On 10.03.21 21:07, Michel Macena Oliveira wrote:
> > At least that's what I expected, but my latencies are much bigger than
> > Cyclictest ones.
> > From cyclictest I get an average in my computer of something between
> > 2300 and 2500 nanoseconds. However, in my application I'm having
> > something between 47000 and 55000 nanoseconds. As you can see it is
> > much higher!
> >
> > I'm not sure of what I'm doing wrong, could you help or suggest something?
>
> Check if your system uses power managment. cyclictest disables the power
> management by using the /dev/cpu_dma_latency API.
>
> HTH,
> Daniel
next prev parent reply other threads:[~2021-03-11 14:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 20:07 PREEMPT_RT benchmark Michel Macena Oliveira
2021-03-11 12:27 ` Daniel Wagner
2021-03-11 13:38 ` John Ogness
2021-03-11 14:56 ` Michel Macena Oliveira [this message]
2021-03-11 16:17 ` Ahmed S. Darwish
2021-03-11 17:02 ` Michel Macena Oliveira
2021-03-11 17:56 ` Ahmed S. Darwish
2021-03-12 15:45 ` Michel Macena Oliveira
2021-03-11 12:58 ` Ahmed S. Darwish
2021-03-11 15:03 ` Michel Macena Oliveira
2021-03-11 16:01 ` Ahmed S. Darwish
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