Date: Wed, 28 Aug 2013 11:48:43 +0200 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-stable@freebsd.org Subject: Re: Suggest changing dirhash defaults for FreeBSD 9.2. Message-ID: <kvkh1j$7fj$1@ger.gmane.org> In-Reply-To: <521D7552.5080008@UToledo.edu> References: <521C9E85.4060801@UToledo.edu> <CAE-mSOLCYRM0LRLRgmaEZN1u5ozttJZC3kWtw3Zarqik1N29zw@mail.gmail.com> <521D7552.5080008@UToledo.edu>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2TFUBVIQGHKUAUIOTNOCI Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 28/08/2013 05:58, Robert Burmeister wrote: >=20 > On 8/27/2013 9:40 AM, Sergey Kandaurov wrote: >> On 27 August 2013 16:41, Robert Burmeister >> <Robert.Burmeister@utoledo.edu> wrote: >>> I have been experimenting with dirhash settings, and have scoured the= >>> internet for other peoples' experience with it. >>> (I found the performance improvement in compiling has forestalled the= >>> need to add an SSD drive. ;-) >>> >>> I believe that increasing the following values by 10 would benefit >>> most FreeBSD users without disadvantage. >>> >>> vfs.ufs.dirhash_maxmem: 2097152 to 20971520 >>> >>> vfs.ufs.dirhash_reclaimage: 5 to 50 or 60 >> vfs.ufs.dirhash_maxmem is further autotuned based on available >> physical memory. >> See r214359 for details. >> > [Spock Eyebrow of Thought] >=20 > I'm running FreeBSD i386 9.2, that allows a max of 4 Gigs of RAM. To what value does the algorithm tune in your case? On my 16 GB machine, it's ~~ 25 MB: vfs.ufs.dirhash_maxmem: 26968064 > I think the algorithm is still overly conservative for 32 bit systems, > which are more likely to be using UFS. >=20 > As 64 bit platforms tend to have more RAM and use ZFS, > is the same tuning algorithm appropriate for both? The policy is to use fractions of the installed RAM (though in a roundabout way), so it should scale reasonably well to both systems with large and small memories. I'll bump vfs.ufs.dirhash_reclaimage to 60, it's worth it. ------enig2TFUBVIQGHKUAUIOTNOCI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlIdx3sACgkQ/QjVBj3/HSwqAwCfYUa6VKsM+xKlyx9DIxKjjDPT u/cAnRYdBxuUFsY/yj3DBPw62mdOmBl5 =MuBK -----END PGP SIGNATURE----- ------enig2TFUBVIQGHKUAUIOTNOCI--
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