Date: Fri, 30 Nov 2007 10:16:26 +0300 From: Alexey Popov <lol@chistydom.ru> To: Pete French <petefrench@ticketswitch.com> Cc: killing@multiplay.co.uk, freebsd-stable@freebsd.org, max@love2party.net Subject: Re: Also seeing 2 x quad-core system slower that 2 x dual core Message-ID: <474FB8CA.8020608@chistydom.ru> In-Reply-To: <E1IxvGp-000Mfu-Q7@dilbert.ticketswitch.com> References: <E1IxvGp-000Mfu-Q7@dilbert.ticketswitch.com>
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Hi Pete French wrote: >> Have you checked that your dir hash isn't suffering due to lack of memory >> this can have a marked impact on seemingly trivial things like this as >> could silly things like the RAID card being installed in a different slot. > > RAID card is onboard on these things - how would I check the dir hash ? The > slower server has 16 gig of RAM, the faster one has 4 gig. Both were > installed the same way in the same order, so should have the same disc layout > more or less. dirhash is a cache of directories that store many files. FreeBSD has unreasonably small default for the maximum size of this cache. See sysctl -a | grep dirhash and tune up vfs.ufs.dirhash_maxmem if vfs.ufs.dirhash_mem is near to the limit. Also could you please provide `top` and `systat -vm 1` output on dual- and quad-core systems during your tests? With best regards, Alexey Popov
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