Date: Wed, 26 Jul 2006 16:17:45 -0700 From: "Jin Guojun [VFFS]" <jin@george.lbl.gov> To: "R. B. Riddick" <arne_woerner@yahoo.com> Cc: freebsd-performance@freebsd.org, Raymond Owens <owensr@comcast.net> Subject: Re: question concerning proper usage of kernel variables net.bpf.bufsize and vm_kmem_size_max Message-ID: <44C7F819.9020504@george.lbl.gov> In-Reply-To: <20060726072753.17138.qmail@web30312.mail.mud.yahoo.com> References: <20060726072753.17138.qmail@web30312.mail.mud.yahoo.com>
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R. B. Riddick wrote: >--- Raymond Owens <owensr@comcast.net> wrote: > > >>Questions: >>Can VM_KMEM_SIZE_MAX be set manually with sysctl? >> >> >> >No, but you could set it with this procedure: >1. Insert the lines > vm.kmem_size=123456789 > vm.kmem_size_max=1234567890 >in > /boot/loader.conf > >2. reboot > >That should change those values... >(see src/sys/kern/kern_malloc.c) > >I wonder, why your box needs such a big buffer? Do u have network traffic >bursts or so? > > Regardless what purpose is for, the net.bpf.bufsize should never set above hardware cache size. The best (optimal size) is 50% - 80% of the hardware cache size, unless original BPF is modified in some way I do not know. Such high bufsize will degrade performance. -- ------------ Jin Guojun ----------- v --- jin@george.lbl.gov --- Distributed Systems Department http://www.dsd.lbl.gov/~jin Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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