From: George Dunlap <george.dunlap@eu.citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xen.org>
Subject: Re: credit2 question
Date: Thu, 24 Jan 2013 09:49:18 +0000 [thread overview]
Message-ID: <5101039E.4060504@eu.citrix.com> (raw)
In-Reply-To: <5100F37702000078000B8FC2@nat28.tlf.novell.com>
On 24/01/13 07:40, Jan Beulich wrote:
> George,
>
> I'm getting puzzled by the second c2t() invocation in
> csched_runtime(): Why is the difference of credits being passed
> here? Doesn't that (unless svc->credit is non-positive, i.e. in all
> but unusual cases) guarantee time > ntime, and particularly
> allow for negative ntime?
Ah, right -- yes, if the other guys' credit is positive, "ntime" is
guaranteed to be lower. Since c2t() involves integer division, it would
definiteyl be good to get rid of the extra call if we can.
My general principle is to make the code clear and easily readable
first, and then do optimization afterwards -- in this case I just never
came back and did the optimization step.
Were you intending to submit a patch for this, or shall I?
-George
next prev parent reply other threads:[~2013-01-24 9:49 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-24 7:40 credit2 question Jan Beulich
2013-01-24 9:49 ` George Dunlap [this message]
2013-01-24 9:53 ` George Dunlap
2013-01-24 10:06 ` Jan Beulich
2013-01-24 10:07 ` George Dunlap
2013-01-24 10:42 ` Jan Beulich
2013-01-24 10:56 ` George Dunlap
2013-01-24 11:10 ` George Dunlap
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