Date: Mon, 23 Aug 2010 22:28:20 -0400 From: jhell <jhell@DataIX.net> To: Artem Belevich <fbsdlist@src.cx> Cc: freebsd-hackers@freebsd.org, zfs-devel@freebsd.org, Andriy Gapon <avg@freebsd.org> Subject: Re: ZFS arc_reclaim_needed: better cooperation with pagedaemon Message-ID: <4C732E44.50702@DataIX.net> In-Reply-To: <AANLkTikGBWStNkyL=J3wXWzDsUftSLsum1vKryB7dU2T@mail.gmail.com> References: <4C719AB9.9020006@freebsd.org> <AANLkTinreSt_Dk_J5vpZ6xrs=snqYu8zKfO0X6H-x_n3@mail.gmail.com> <4C721161.40403@freebsd.org> <AANLkTikg3e%2BGvZNtb5Uk3yAvWYwrgfF-4Rx0dDdooyQM@mail.gmail.com> <4C72DD1A.9070204@DataIX.net> <4C72DDC3.1000006@DataIX.net> <AANLkTikGBWStNkyL=J3wXWzDsUftSLsum1vKryB7dU2T@mail.gmail.com>
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On 08/23/2010 22:10, Artem Belevich wrote: > First prepare the data. > * You'll need some files totalling around the amount of physical > memory on your box. Multiple copies of /usr/src should do the trick. > * Place one copy on UFS filesystem and another on ZFS > > Experiment #1: > * Prime ARC by tarring dataset on ZFS into /dev/null. > * Now tar both datasets in parallel with output to /dev/null > > Previously you would end up with ARC size shrinking down to arc_min. > What I hope to see after the patch is that inactive memory and ARC > reach some sort of equilibrium with neither monopolizing all available > memory. > > #Experiment #2: > If equilibrium is reached, try running some application that would > allocate and use about 1/2 of your physical memory. > Something like that perl one-liner used to cause memory shortage, only > a bit less drastic. > perl -e '$x="x"x1_000_000_000'; # this should allocate about 2GB. > Tune the number to suit your system. > > Again, in the past ARC would be the one feeing up the memory. Let's > see if inactive list gives up some, too. Alright I should be able to have something together with the output of this by the 25th with my current workload being the ultimate determining factor. PBS, Regards, -- jhell,v
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