From: Philippe Gerum <rpm@xenomai.org>
To: Russell Johnson <russell.johnson@kratosdefense.com>
Cc: xenomai@xenomai.org
Subject: Re: In-band Context Switch on oob_ioctl() call
Date: Sat, 19 Feb 2022 16:29:26 +0100 [thread overview]
Message-ID: <877d9qho0c.fsf@xenomai.org> (raw)
In-Reply-To: <PH1P110MB105036E4A7D3954173E4C536E2379@PH1P110MB1050.NAMP110.PROD.OUTLOOK.COM>
Russell Johnson via Xenomai <xenomai@xenomai.org> writes:
> Hello,
>
> I have added the oob_ioctl file descriptor to my driver, and I have
> made sure that I call the necessary evl functions in the open()
> function in the driver as well. I have a test app in userspace that is
> simply opening the driver and issuing an oob_ioctl every second. What
> I am seeing in the output from "evl ps -l" is that the "ISW" and
> "CTXSW" fields are incrementing with every oob_ioctl call. I added in
> the O_OOB flag to my open call, and I am still seeing the same
> behavior. I don't get why it would be switching to in-band every time
> the oob_ioctl() is called. Any ideas on what I could be doing wrong?
>
> Thanks,
> Russell
It looks like the calling thread is undergoing the so-called weak
scheduling policy, see [1].
[1] https://evlproject.org/core/user-api/scheduling/#SCHED_WEAK
--
Philippe.
next prev parent reply other threads:[~2022-02-19 15:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-18 18:24 In-band Context Switch on oob_ioctl() call Russell Johnson
2022-02-19 15:29 ` Philippe Gerum [this message]
2022-02-21 15:25 ` [External] - " Russell Johnson
2022-02-21 17:32 ` Philippe Gerum
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