On Fri, May 12, 2006 at 09:59:56AM -0700, Richard Elling wrote: > On Fri, 2006-05-12 at 10:42 -0500, Anton Rang wrote: > > > Now latency wise, the cost of copy is small compared to the > > > I/O; right ? So it now turns into an issue of saving some > > > CPU cycles. > > > > CPU cycles and memory bandwidth (which both can be in short > > supply on a database server). > > We can throw hardware at that :-) Imagine a machine with lots > of extra CPU cycles and lots of parallel access to multiple > memory banks. This is the strategy behind CMT. In the future, > you will have many more CPU cycles and even better memory > bandwidth than you do now, perhaps by an order of magnitude > in the next few years.
Well, yes, of course, but I think the arguments for direct I/O are excellent. Another thing that I see an argument for is limiting the size of various caches, to avoid paging (even having no swap isn't enough as you don't want memory pressure evicting hot text pages). Nico -- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
