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Date:      Tue, 02 Jul 2013 21:08:36 +0300
From:      Andriy Gapon <avg@FreeBSD.org>
To:        attilio@FreeBSD.org
Cc:        svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org
Subject:   Re: should_yield problem [Was: svn commit: r251322 - head/sys/kern]
Message-ID:  <51D31724.6090807@FreeBSD.org>
In-Reply-To: <CAJ-FndATxzTwCkZGXw4jD_8O4KbnHbsjk4DwHwbp%2B0gd3VGTCQ@mail.gmail.com>
References:  <201306031736.r53Hain5093431@svn.freebsd.org> <51D30463.50608@FreeBSD.org> <CAJ-FndD5tCxe-L8V73MFtk_4xr0Wq3MHasKY4O_tcA3uYouKAw@mail.gmail.com> <51D30CE8.7030803@FreeBSD.org> <CAJ-FndATxzTwCkZGXw4jD_8O4KbnHbsjk4DwHwbp%2B0gd3VGTCQ@mail.gmail.com>

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on 02/07/2013 20:52 Attilio Rao said the following:
> I was just pointing out that the real bug is not in the subtraction
> itself but on the hogticks comparison.
> This is because hogticks is not an absolute measurement but it
> represents really a ticks difference.
> In my opinion we should define hogticks as an unsigned int and add a
> small comment saying that it is a differential.
> This will fix the issue.

I think that my original suggestion is equivalently well if not more obvious.
This is a common knowledge:
http://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution

distance = (signed)( i1 - i2 )

-- 
Andriy Gapon



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