Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 7 Sep 2013 13:39:36 -0700
From:      Adrian Chadd <adrian@freebsd.org>
To:        Ian Lepore <ian@freebsd.org>
Cc:        FreeBSD Net <freebsd-net@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>
Subject:   Re: mbuf autotuning effect
Message-ID:  <CAJ-Vmon03Es2WJp%2B0p-_XuTdfqc8=daO8w1Kp4M=t0aNBoAruA@mail.gmail.com>
In-Reply-To: <1378583762.1111.512.camel@revolution.hippie.lan>
References:  <CALCpEUHoAS2RRyO7JVOeSKWKiss9vZmN%2BxA1BDpwHDpkEYcjEA@mail.gmail.com> <CAJ-VmomAjsU%2Bnc=4AEdSn5gDhspc2YVrDtPophJvmee1kSTYog@mail.gmail.com> <9CBFAD35-D651-4E28-BEBB-DC3717F38567@bsdimp.com> <CALCpEUHh9o-scuoj_p-MGMZKn2d_Bbhtf8djV8MsLeOF8%2BKG9A@mail.gmail.com> <1378583762.1111.512.camel@revolution.hippie.lan>

next in thread | previous in thread | raw e-mail | index | archive | help
On 7 September 2013 12:56, Ian Lepore <ian@freebsd.org> wrote:


> I think the part of this that strikes me as strange is calling 20% of
> physical memory used for network buffers a "very low value".  It seems
> outrageously high to me.   I'd be pissed if that much memory got wasted
> on network buffers on one of our $work platforms with so little memory.
>
> So the fact that you think it's crazy-low and I think it's crazy-high
> may be a sign that it's auto-tuned to a reasonable compromise, and in
> both our cases the right fix would be to use the available knobs to tune
> things for our particular uses.
>

Well, which limit is actually being hit here? 20% of 32mb is still a lot of
memory buffers..

Now, for sizing up the needed buffers for wifi:

assuming 512 tx, 512 rx buffers for two ath NICs.

another 512+512 buffers for each arge NICs.

So, 4096 mbufs here, 2k each, so ~ 8mb of RAM.

Amusing..



-adrian



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAJ-Vmon03Es2WJp%2B0p-_XuTdfqc8=daO8w1Kp4M=t0aNBoAruA>