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Date: Wed, 22 Sep 2004 00:47:04 -0700
From: Bruce M Simpson <bms@spc.org>
To: Zongsheng Zhang <zhang@ist.osaka-u.ac.jp>
Message-ID: <20040922074704.GD4985@empiric.icir.org>
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Subject: Re: which parameter == txqueuelen of linux ??
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On Wed, Sep 22, 2004 at 02:55:28PM +0900, Zongsheng Zhang wrote:
> In Linux, txqueuelen (the length of the transmit queue of the device)
> can be set by 'ifconfig' command. Is there a corresponding parameter or
> command in BSD??

I assume that in Linux, 'txqueuelen' actually refers to the maximum (bounded)
size of the device's transmit queue before Linux's equivalent of the
IFF_OACTIVE flag is set (device transmit queue full and no more data may
be queued).

The short answer is no. The long answer is it depends; some device drivers
offer a means of doing so, but it's not standard by any means. Most
network interfaces in FreeBSD set their if_snd.ifq_maxlen to IFQ_MAXLEN,
which is 50 by default.

In some cases the device driver won't permit you to touch this value because
it's hardcoded to match the size of a descriptor ring which the chip uses for
data transmission.

BMS