Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 7 Jul 2014 21:32:52 +0200
From:      John Hay <jhay@meraka.org.za>
To:        hiren panchasara <hiren.panchasara@gmail.com>
Cc:        "freebsd-wireless@freebsd.org" <freebsd-wireless@freebsd.org>, "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org>, Ian Lepore <ian@freebsd.org>
Subject:   Re: CAMBRIA and more than one atheros card
Message-ID:  <20140707193252.GA79553@zibbi.meraka.csir.co.za>
In-Reply-To: <CALCpEUG1hCqHW8dKxSzPeaAJW5aevY_wHwWzoF%2Bfv9ypju-8wg@mail.gmail.com>
References:  <20140707142538.GA43661@zibbi.meraka.csir.co.za> <CAJ-VmompzxOYXQ0_bmGsRHH7dGahEEGRsv-OqPMgAdB2NVOaaw@mail.gmail.com> <1404753166.65432.10.camel@revolution.hippie.lan> <CAJ-Vmo=zY%2B6J24s3Ux5LR7UVaQ3N5=eXHfAG-cOxXWbhJoHCGA@mail.gmail.com> <20140707182814.GA75629@zibbi.meraka.csir.co.za> <CAJ-VmokGC6-DHQP1V9exEq-VPW-oN972uYSbZQDuq4KiPb1SeA@mail.gmail.com> <CALCpEUG1hCqHW8dKxSzPeaAJW5aevY_wHwWzoF%2Bfv9ypju-8wg@mail.gmail.com>

next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Jul 07, 2014 at 11:59:03AM -0700, hiren panchasara wrote:
> On Mon, Jul 7, 2014 at 11:31 AM, Adrian Chadd <adrian@freebsd.org> wrote:
> > On 7 July 2014 11:28, John Hay <jhay@meraka.org.za> wrote:
> >> On Mon, Jul 07, 2014 at 11:22:46AM -0700, Adrian Chadd wrote:
> >>> On 7 July 2014 10:12, Ian Lepore <ian@freebsd.org> wrote:
> >>> > On Mon, 2014-07-07 at 09:25 -0700, Adrian Chadd wrote:
> >>> >> hi,
> >>> >>
> >>> >> That call is returning ENOMEM. I'm not sure why. It allocated an mbuf
> >>> >> fine, but it couldn't allocate the DMA map.
> >>> >>
> >>> >> What's the output of "vmstat -z" ? I wonder if it's failing an allocation.
> >>> >>
> >>> >>
> >>> >>
> >>> >> -a
> >>> >
> >>> > Lack of bounce buffers is a posibility that won't show up in vmstat
> >>> > output.
> >>>
> >>> right, but there's a bunch of already failing vmstat entries.
> >>>
> >>>
> >>> John - there's a vmscale parameter somewhere. Hiren had to drop it
> >>> down for his APs to work in 64MB of RAM. I think it's
> >>> vm.kmem_size_scale . What's it say for you?
> >>>
> >>
> >> :~ # sysctl vm.kmem_size_scale
> >> vm.kmem_size_scale: 3
> >
> > Ok. Search the archives for an email from Hiren titled "mbuf autotuning effect".
> >
> > TL;DR - set it to 1 and recompile. There's a kernel option somewhere
> > to do exactly that.
> 
> Yes. http://lists.freebsd.org/pipermail/freebsd-mips/2013-September/003081.html
> 
> I went through this for my tplink.
> 
> John, can you show o/p of:
> 
> sysctl -a | grep hw | grep mem
> and
> sysctl -a | grep maxmbuf

I already compiled a new kernel with "options VM_KMEM_SIZE_SCALE=1" and
the problems went away. :-) On the new kernel the output is:

##########################
:~ # sysctl -a | grep hw | grep mem
hw.physmem: 128196608
hw.usermem: 103845888
hw.realmem: 134213632
:~ # sysctl -a | grep maxmbuf
kern.ipc.maxmbufmem: 62705664
##########################

I rebooted with the old kernel and its output is:

##########################
:~ # sysctl -a | grep hw | grep mem
hw.physmem: 128196608
hw.usermem: 104124416
hw.realmem: 134213632
:~ # sysctl -a | grep maxmbuf
kern.ipc.maxmbufmem: 20901888
##########################

So for the heck of it, I ran my script again and this time it successfully
configured the 3 atheros interfaces. ? How can that be? One other thing I
also do not understand. I have an Avila (with 64M RAM, half of the CAMBRIA),
also with 3 atheros cards and there it always works.

But if "options VM_KMEM_SIZE_SCALE=1" keeps the problem away, then I'll
leave that in my kernel. :-)

Thanks for everyone that helped.

John
-- 
John Hay -- jhay@meraka.csir.co.za / jhay@meraka.org.za



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20140707193252.GA79553>