On Wed, Dec 21, 2011 at 1:16 PM, Randy Schultz <schu...@earlham.edu> wrote: > On Tue, 20 Dec 2011, Matthew Tippett spaketh thusly: > > -}There are still possible issues with those benchmarks. The Xeon has known > -}problems scaling from 6 to 12 cores (well enabling the hyperthreading), so > you > -}may find that some platforms are penalized in performance if HT is turned > on. > -}See the scaling that Phoronix has done in > -} > -}http://openbenchmarking.org/result/1112166-AR-1112153AR03 > -} > -}Most systems are good with scaling on real cores, the hyperthreading (and > for > -}that matter the Bulldozer thread affinity) can really break performance. > -}Different platforms have different behaviours. Benchmarking is a mucky > -}business.. > > This brings up a good point. While I don't have any hard #'s, I suspect the > vast majority of SA's do not have/spend much time tweaking this and tuning > that. > Order the box, drop the OS on it, install needed bits and go. Saying "oh for > app X you need to tune these sysctl's", while it may be entirely true, kinda > throws things out the window. It seems that once one starts down that > slippery > slope, it merely becomes a game of how much time to you have to "tune 1 more > thing". ;> I think Phoronix has the right idea of just grabbing a stock box > and not looking into what needs to be tweaked for a specific app. >
I think that a good SA will at least consider how drives are arranged. We don't just slap ZFS on a single disk and expect magic to happen, we consider how write heavy a system will be and consider a dedicated ZIL, we consider what proportion of files will be re-read and how much application memory will be required and adjust ARC and L2ARC accordingly. Tuning and foresight are important. Cheers Tom _______________________________________________ freebsd-performance@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "freebsd-performance-unsubscr...@freebsd.org"
