Date: Sat, 7 Sep 2013 22:57:27 -0700 From: hiren panchasara <hiren.panchasara@gmail.com> To: Adrian Chadd <adrian@freebsd.org> Cc: FreeBSD Net <freebsd-net@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>, Ian Lepore <ian@freebsd.org> Subject: Re: mbuf autotuning effect Message-ID: <CALCpEUGMth00BdACdmAy%2BmhXcCVVTqpx23zwZrpZMeAb4fUxxg@mail.gmail.com> In-Reply-To: <CAJ-Vmon03Es2WJp%2B0p-_XuTdfqc8=daO8w1Kp4M=t0aNBoAruA@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>
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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. cheers, Hiren
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