netdev - Re: [PATCH] netem: add cell concept to simulate special MAC behavior

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Message-ID: <20111210235822.GM17840@Chamillionaire.breakpoint.cc>
Date:	Sun, 11 Dec 2011 00:58:22 +0100
From:	Florian Westphal <fw@...len.de>
To:	Hagen Paul Pfeifer <hagen@...u.net>
Cc:	netdev@...r.kernel.org, eric.dumazet@...il.com,
	shemminger@...tta.com, Florian Westphal <fw@...len.de>
Subject: Re: [PATCH] netem: add cell concept to simulate special MAC behavior

Hagen Paul Pfeifer <hagen@...u.net> wrote:
> +static psched_time_t packet_len_2_sched_time(unsigned int len, struct netem_sched_data *q)
>  {
[..]
> +	if (q->cell_size) {
> +		u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);
> +		u32 mod_carry = len - cells * q->cell_size;
> +
> +		if (mod_carry)
> +			mod_carry = (len > q->cell_size || !cells) ?
> +				q->cell_size - mod_carry : len - mod_carry;
> +
> +		if (q->cell_overhead) {
> +			if (mod_carry)
> +				++cells;
> +			len += cells * q->cell_overhead;
> +		}
> +
> +		len += mod_carry;

Why did you chose to replace the previous version?

if (q->cell_size) {
      u32 cells = reciprocal_divide(len, q->cell_size_reciprocal);

      if (len > cells * q->cell_size)  /* extra cell needed for remainder */
                        cells++;
      len = cells * (q->cell_size + q->cell_overhead);
}

I think that it is a lot easier to read -- did you find a problem with it?
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