From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 4 Mar 2022 12:35:05 +0100 (CET)
From: Richard Weinberger <richard@nod.at>
Message-ID: <1971847999.108624.1646393705887.JavaMail.zimbra@nod.at>
Subject: Questiion on commit: demo/cyclictest: fix time delta calculation
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To: xenomai <xenomai@xenomai.org>

Hello,

I'm investigating into a cyclictest issue where it reports negative values just like this commit states:
https://source.denx.de/Xenomai/xenomai/-/commit/3069a7bbc48559f4d2a6184d6159b771f193a4e9

Since I'm on Xenomai 3.1.2 the said commit is already included.
But I have a hard time to understand what problem the commit actually fixes.
Why is the old calculation wrong?

PREEMPT_RT's rt-test does it the same way:
https://git.kernel.org/pub/scm/utils/rt-tests/rt-tests.git/tree/src/include/rt-utils.h#n60

Except that it casts tv_secs/tv_nsecs to int first, which shouldn't make a difference.

Thanks,
//richard