2010/6/5 Kostik Belousov <kostik...@gmail.com> > > On Sat, Jun 05, 2010 at 07:41:23PM +0200, Attilio Rao wrote: > > 2010/6/5 Matthew Jacob <m...@feral.com> > > > > > > All of these tests have been apples vs. oranges for years. > > > > > > The following seems to be true, though: > > > > > > a) FreeBSD sequential write performance in UFS has always been less than > > > optimal. > > > > > > b) Linux sequential write performance in just about any filesystem has > > > always been "impressive". But that "impressive" has come at some not so > > > obvious costs. First of all, Linux is probably the most aggressive > > > cluster/write-behind OS I've even seen. You can suck down all available > > > memory with writebehind using dd. This means that some stats are > > > "impressive", and others are "painful". A desktop that becomes completely > > > unresponsive while you're doing this dd is one personal outcome. > > > > > > Also, you have to be careful what you're asking for in comparing the two > > > platforms, or any platforms for that matter. What do you want to optimize > > > for? Apparent responsiveness as a desktop? A specific workload (nfs, > > > cifs) that completes N quatloos per fortnight? > > > > Besides anything, I'm much more concerned about the loss of > > performance within FreeBSD itself. I wouldn't expect a so high > > pessimization when the number of threads increases (without > > considering the big performance loss with the 8k blocksize, pretty > > much reproducible). I'm trying to drive, privately, the tester to > > pmc/lock profiling analysis in order to start collecting some useful > > datas. > Are the benchmarks create threads that write to the same file ? > If yes, then this behaviour is well understood.
Actually I still don't know as I just sent an e-mail to the tester and he didn't followup still. However I'm not entirely sure this is a full bottleneck which may be reconduit to missing of byte-range locking. I want to dig more and better understand what's going on exactly. Attilio -- Peace can only be achieved by understanding - A. Einstein _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
