Date: Fri, 7 Dec 2007 14:41:47 +0100 From: "Claus Guttesen" <kometen@gmail.com> To: "Pete French" <petefrench@ticketswitch.com> Cc: freebsd-stable@freebsd.org Subject: Re: Also seeing 2 x quad-core system slower that 2 x dual core Message-ID: <b41c75520712070541g2e6969f8s8c0baef789da7c40@mail.gmail.com> In-Reply-To: <E1J0cUE-000CkR-6X@dilbert.ticketswitch.com> References: <E1IxklH-000ElU-3w@dilbert.ticketswitch.com> <E1J0cUE-000CkR-6X@dilbert.ticketswitch.com>
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> Just as a followup to this - I soent some time going through all > the suggestions and advice that people gave me regarding this problem. > It turns out that the newer servers shipped by HP have different cache > settings to the older ones on their RAID controllers, plus I get very > different results from my benchmarks depending on how long the machines > have been booted for and what activity has occurred on them (probably due to > things ending up in cache). What settings are there on the cache? I have a DL 380 G5 with 2 x dual-core woodcrest and 512 MB BB cache running as a db-server (postgresql) and two DL 360 G5 with with 2 x 4-core and 256 MB BB cache running as web-servers. > Upshot - if the machines are configured identically, and an identical install > is made and an identical test doen then we get identical performance as > expected. > > Part of the reason for posting this though is that a lot of people have bbeen > worrying about 8x CPU performance, and this thread won't have helped. So > I wanted to say that now I am convinced that (for my workload) these machines > are fine. To the point where I have installed 7.0-BETA4 on the ten new > 8 core servers for a very large load on th webfarm this morning. I'm pleased > toio say that it went off perfectly, the servers took the load and we had > no problems at all. We are running CGI scripts against mySQL under apache22 > basically - which is a pretty common thing to do. Ia m using ULE and tthe > amd64 version of the OS. I will second this even though I do not have hard facts to base this assumption on. I have - as mentioned above - two web-servers running 7.0 beta 2 on a 8-core and is satisfied with the performance. But my only comparison are two 2 x dual-core opterons (4-way) where the 8-core handles approx. twice as much load. But maby I should expect 2.5 as much performance since the quad-core is a newer cpu and the opterons are getting two years old. I also upgraded our db-server from 6.2 RC1 to 7.0 beta 3 on our DL 380 G5 (4-way) because the server was getting constrained on ressources. I could either replace my 10K rpm drives (in raid 1+0) with 15K ditto which would require a downtime which we could not afford at this time or I could upgrade from 6.2 to 7.0. The upgrade took 10 min. Kernel and userland had all ready been compiled on the web-server. The upgrade was worthwhile and the db-server is performing better. On Sunday I will have some load-numbers and post them on Monday. -- regards Claus When lenity and cruelty play for a kingdom, the gentlest gamester is the soonest winner. Shakespeare
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