From: John Ogness <john.ogness@linutronix.de>
To: Daniel Wagner <wagi@monom.org>,
Michel Macena Oliveira <michel@austral-dynamics.com>,
linux-rt-users@vger.kernel.org
Subject: Re: PREEMPT_RT benchmark
Date: Thu, 11 Mar 2021 14:38:57 +0100 [thread overview]
Message-ID: <87o8fpyfm6.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <9be68ca5-9fec-161c-1b37-1b47c0a1d845@monom.org>
On 2021-03-11, Daniel Wagner <wagi@monom.org> wrote:
> 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.
In addition, avoid file I/O in your real-time thread. Store your
calculations in a variable and let another thread read it and write to
disk. Then it would be more "equivalent to Cyclict test".
John Ogness
next prev parent reply other threads:[~2021-03-11 13:40 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 [this message]
2021-03-11 14:56 ` Michel Macena Oliveira
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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