Subject: Re: packet capturing
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Perry E. Metzger <>
List: tech-kern
Date: 01/21/2004 16:02:26
Jonathan Stone <jonathan@DSG.Stanford.EDU> writes:
>>This argues for adding a comment, perhaps
>>  /* XXX Set at boot time based on available memory. */
> Sure, which is why the second patch I posted has:
> +int bpf_maxbufsize = (256 * 1024)      /* XXX should be set dynamically */
> I use grep a lot, so I was trying to fit the comment on the same line
> as the variable.  256K is where I crossed over the point of
> diminishing returns on a 133MHz Pentium (Intel Endeavour motherboard).
> After sleeping on it, it should really be 1Mbyte or so for modern
> machines with gigabit ethernet.

One reason for wanting it dynamic is that inevitably, machines will
get more memory and faster networks, so it is better that we not have
to have this discussion in N years again... :)

We should have the sysctl. On a separate note, we should have the
default set based on system memory, and if we don't have an easy
mechanism for sizing such thing now, we really could use one for all
sorts of things.

Perry E. Metzger