Date: Wed, 18 Sep 2013 21:39:16 -0700 From: hiren panchasara <hiren.panchasara@gmail.com> To: Adrian Chadd <adrian@freebsd.org> Cc: "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>, Ian Lepore <ian@freebsd.org>, freebsd-embedded <freebsd-embedded@freebsd.org> Subject: Re: mbuf autotuning effect Message-ID: <CALCpEUG%2Bn_5VxnZVGTexg-UYxy=HF4qr4a6P-eAip1Ws2wjo2g@mail.gmail.com> In-Reply-To: <CALCpEUGMth00BdACdmAy%2BmhXcCVVTqpx23zwZrpZMeAb4fUxxg@mail.gmail.com> 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> <CAJ-Vmon03Es2WJp%2B0p-_XuTdfqc8=daO8w1Kp4M=t0aNBoAruA@mail.gmail.com> <CALCpEUGMth00BdACdmAy%2BmhXcCVVTqpx23zwZrpZMeAb4fUxxg@mail.gmail.com>
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Removing -net@, Adding -embedded@ On Sat, Sep 7, 2013 at 10:57 PM, hiren panchasara < hiren.panchasara@gmail.com> wrote: > > > > On Sat, Sep 7, 2013 at 1:39 PM, Adrian Chadd <adrian@freebsd.org> wrote: > >> 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. >> > > And we are only getting 6mb of maxmbufmem with current setup. > > Index: mips/include/vmparam.h > =================================================================== > --- mips/include/vmparam.h (revision 255320) > +++ mips/include/vmparam.h (working copy) > @@ -119,7 +119,7 @@ > * is the total KVA space allocated for kmem_map. > */ > #ifndef VM_KMEM_SIZE_SCALE > -#define VM_KMEM_SIZE_SCALE (3) > +#define VM_KMEM_SIZE_SCALE (1) > #endif > > /* > > As I mentioned on another reply in the same thread, VM_KMEM_SIZE_SCALE is > 1 for amd64. If I do the same for mips as above, we get > > # sysctl -a | grep maxmbuf > kern.ipc.maxmbufmem: 14407680 > > Now, do we want to have this much rams assigned to mbufs is another > question. > I am proposing following change for tplink TP-WN1043ND. This will get maxmbufmem *up* from 6mb to 14mb out of total 32mb. Index: sys/mips/conf/TP-WN1043ND =================================================================== --- sys/mips/conf/TP-WN1043ND (revision 255680) +++ sys/mips/conf/TP-WN1043ND (working copy) @@ -15,6 +15,8 @@ # Force the board memory - 32mb options AR71XX_REALMEM=32*1024*1024 +options VM_KMEM_SIZE_SCALE=1 + # i2c GPIO bus device gpioiic device iicbb I do not see any other side-effects of it. Please correct me if I am wrong. cheers, Hiren
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