Date: Fri, 14 Jul 2000 14:13:13 +0100 From: Ben Smithurst <ben@FreeBSD.org> To: John Baldwin <jhb@FreeBSD.ORG> Cc: Neil Blakey-Milner <nbm@mithrandr.moria.org>, freebsd-doc@FreeBSD.ORG, Nik Clayton <nik@FreeBSD.ORG> Subject: Re: FAQ addition Message-ID: <20000714141313.O48641@strontium.scientia.demon.co.uk> In-Reply-To: <XFMail.000714014800.jhb@FreeBSD.org> References: <20000714102522.A61949@mithrandr.moria.org> <XFMail.000714014800.jhb@FreeBSD.org>
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[-- Attachment #1 --] John Baldwin wrote: > This actually is not quite true. You don't want 0 free memory. :) > A better way to phrase this might be to explain that the cached data > allows the system to use up available free memory to remember things > that it has recently used allowing it to avoid having to use the > slow disk as often, and thus increasing performance. Free memory is > the memory left over after the caching. Or something along those > lines. ok, is something like this better? <para>The simple answer is that free memory is wasted memory. Any memory that your programs don't actively allocate is used within the FreeBSD kernel as disk cache. The values shown by &man.top.1; labelled as <literal>Inact</literal>, <literal>Cache</literal>, and <literal>Buf</literal> are all cached data at different aging levels. This cached data means the system does not have to access a slow disk again for data it has accessed recently, thus increasing overall performance. In general, a low value shown for <literal>Free</literal> memory in &man.top.1; is good, provided it is not <emphasis>very</emphasis> low.</para> -- Ben Smithurst / ben@FreeBSD.org / PGP: 0x99392F7D FreeBSD Documentation Project / [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 5.0i for non-commercial use MessageID: 3uMnrlDONxbpu80+yyaMQDDbVaKKdyd9 iQCVAwUBOW8R6CsPVtiZOS99AQFbLgP/SbUyPMQsCIQm7dxp4XZhzr4bVGKwSX0i qQTjEXdUX34jx3q4Ff8nBM4CN1om5JeMpOCCwS6ON+1ox6+n9UVotTawsJEwxr+P EzD/MTlOvU/LqEcQnLsc3bn+Oz7xxMmReahX6rv9+mVlDlEazgojNgka/T65A5G+ 9hzt8g6SVEA= =6LIx -----END PGP SIGNATURE-----
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