Date: Sun, 03 Dec 2000 17:46:22 -0800 From: David Greenman <dg@root.com> To: "O. Hartmann" <ohartman@ipamzlx.physik.uni-mainz.de> Cc: freebsd-questions@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG Subject: Re: NSFBUFS in kernel config Message-ID: <200012040146.RAA18347@implode.root.com> In-Reply-To: Your message of "Sun, 03 Dec 2000 23:23:00 %2B0100." <Pine.BSF.4.21.0012032320210.385-100000@ipamzlx.physik.uni-mainz.de>
next in thread | previous in thread | raw e-mail | index | archive | help
>Can anyone explain what > options NSFBUFS=1024 or =4096 > > >means? I played around with this option and on a 64MBytes machine, >pushing it to 1024 caused a heavy swapping so I commented out this >option to avoid it. What is a reasonable value for a server system >under heavy load and what for a client, maybe a diskless one? This sets a value for the maximum number of sendfile buffers, which are essentially headers for pages that have been queued for transmit, along with a chunk of kernel virtual memory to map them. If your applications use sendfile() heavily, then this will also have the side-effect of making those [file] pages inelligble to be paged out. It is intended for tuning systems that use sendfile() heavily. I would guess that your applications don't use sendfile(), however, and thus tuning the above will have no effect except to wastefully allocate a lot of kernel virtual memory for something that isn't used. Unless you know what you are doing, you should not set this option in your kernel config file. Since you are setting it (and to the value that is in the LINT kernel config file), this brings up the obvious question of what other LINT options you have turned on. The options in the LINT config file are only for testing the build of the kernel and should not be randomly included in a production kernel config file. You should use the GENERIC config file as a template to make your own, not LINT. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org President, TeraSolutions, Inc. - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200012040146.RAA18347>