Date: Thu, 16 Aug 2012 18:44:46 -0700 From: Garrett Cooper <yanegomi@gmail.com> To: =?ISO-8859-1?Q?Gezeala_M=2E_Bacu=F1o_II?= <gezeala@gmail.com> Cc: freebsd-performance@freebsd.org Subject: Re: vm.kmem_size_max and vm.kmem_size capped at 329853485875 (~307GB) Message-ID: <CAGH67wS=jue7%2B92jSCyaydOLHC=hPwtndV64FVtC7nhDsPvFng@mail.gmail.com> In-Reply-To: <CAJKO3mU8bfn=jmWNSpvAXOR1AWyAAM0Sio1D1PnOYg8P59V9cg@mail.gmail.com> References: <CAJKO3mU8bfn=jmWNSpvAXOR1AWyAAM0Sio1D1PnOYg8P59V9cg@mail.gmail.com>
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On Thu, Aug 16, 2012 at 5:46 PM, Gezeala M. Bacu=F1o II <gezeala@gmail.com>= wrote: > Hello fellow listers, > > On a server with 512GB RAM it appears that vm.kmem_size_max is not > being auto-tuned to use >329853485875 (~307GB). > > On this machine vm.kmem_size is equal to vm.kmem_size_max > > # from sysctl > vm.kmem_size_max: 329853485875 > vm.kmem_size: 329853485875 > > On a machine with 1GB of RAM, I have successfully set vm.kmem_size_max > to 330GB and vm.kmem_size automatically adjusts to 1GB even if I > manually set it in /boot/loader.conf. > > But on the machine with 512GB of RAM it just resets. For the machine > to boot, we need to go to the loader prompt and issue: > > OK set vm.kmem_size_max=3D"300G" > OK boot > > On all PCBSD (8,9) or FreeBSD (8.1,8.2,9) machines we have, > vm.kmem_size_max is always set to 329853485875. > > How can I increase vm.kmem_size_max to use at least 500GB? And how is > 329853485875 determined (formula)? I need to increase vm.kmem_size_max > and vm.kmem_size so I can set vfs.zfs.arc_max (ZFS ARC) to use say > 490GB. > > I'm browsing thru the source code at > http://fxr.watson.org/fxr/search?v=3DFREEBSD9&string=3Dvm.kmem_size_max > and I'm still trying to make sense of how vm.kmem_size_max is > computed. > > I have posted the same topic on forums.freebsd.org but I'm not getting > any recommendations. > > Please see the link for additional details: > http://forums.freebsd.org/showthread.php?t=3D33977 Have you tried defining VM_KMEM_SIZE_MAX to your target value? Its architecture specific BTW... see sys/<architecture>/include/vmparam.h -- look for `VM_KMEM_SIZE_MAX`. Cheers, -Garrett
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