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Date: Tue, 02 Jul 2013 21:11:08 +0300
From: Andriy Gapon <avg@FreeBSD.org>
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To: Ed Maste <emaste@FreeBSD.org>
Subject: Re: should_yield problem [Was: svn commit: r251322 - head/sys/kern]
References: <201306031736.r53Hain5093431@svn.freebsd.org>
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Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org,
 src-committers@FreeBSD.org, Konstantin Belousov <kib@FreeBSD.org>
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on 02/07/2013 20:59 Ed Maste said the following:
> On 2 July 2013 12:48, Andriy Gapon <avg@freebsd.org> wrote:
>> I am not sure if the originally reported problem was also caused by
>> should_yield() or if it was something else.  But in either case I think that we
>> should fix should_yield.  Perhaps (ticks - curthread->td_swvoltick) should be
>> cast to unsigned before comparison?
> 
> What about just initializing td_swvoltick to ticks at td creation?

I like this idea.  Still I think that distance between two wrapping numbers
should be calculated properly even if that mostly would not matter in practice.

distance = (signed)( i1 - i2 )

-- 
Andriy Gapon