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>
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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
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