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From: Julio Kriger <juliokriger@gmail.com>
To: Stephen Hemminger <shemminger@osdl.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	netdev@oss.sgi.com, netem@osdl.org
Subject: Re: [PATCH] netem: fix logic bug in reorder conditional
Date: Tue, 24 May 2005 12:41:11 -0300	[thread overview]
Message-ID: <682bc30a050524084136fa2fe3@mail.gmail.com> (raw)
In-Reply-To: <20050523140055.127f1a9f@dxpl.pdx.osdl.net>

> > 2) If I set latency = 50ms and a jitter = 300ms, tabledist can give me
> > a negative number. This value is addes to cb->time_to_send, so it
> > could change it to a negative value. Should we only accept positives
> > number before add it to cb->time_to_send? or will
> > q->qdisc->enqueue(skb, q->qdisc) put the package on the queue in a
> > special way so it will be handled "before" other packages alrealy on
> > the queue but with gretaer time_to_send?
> 
> probably should bound the value to 0 before the addition, to avoid large
> wraparound problems, but since enqueue checks for for time it will work
> as long as delta less than 2^32/2.
> 

I think the value should be restricted to be positive and greater than
zero. Becuase if a negative number is allowed we will be "losing"
packages to be reordered, hence we will not be reordering, say 25%, of
packages instead we will be reordering about 15%.
In other words, packages that should be reordered will not be
reordered because its new time to send will be the same as the old
time to send.
Regards,
Julio

-- 
----------------------------
Julio Kriger
mailto:juliokriger@gmail.com

  reply	other threads:[~2005-05-24 15:41 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-19 22:12 [PATCH] (3/3) netem: allow random reordering Stephen Hemminger
2005-05-20 20:28 ` [Netem] " Julio Kriger
2005-05-23 17:25   ` Stephen Hemminger
2005-05-21 15:05 ` Julio Kriger
2005-05-21 23:00 ` Julio Kriger
2005-05-23 17:43   ` [PATCH] netem: fix logic bug in reorder conditional Stephen Hemminger
2005-05-23 20:55     ` Julio Kriger
2005-05-23 21:00       ` Stephen Hemminger
2005-05-24 15:41         ` Julio Kriger [this message]
2005-05-24 16:57           ` Stephen Hemminger
2005-05-24 17:27             ` Julio Kriger
2005-05-24 22:26 ` [PATCH] (3/3) netem: allow random reordering (with fix) Stephen Hemminger
2005-05-25 22:08   ` David S. Miller

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