On Fri, 09 Jan 2009 13:30:30 -0500 Lowell Gilbert <freebsd-questions-lo...@be-well.ilk.org> wrote:
> "PstreeM China" <pstr...@gmail.com> writes: > > > i think the option WRKDIRPREFIX is a good idea , and i whill test > > the methon unionfs. > > Definitely benchmark against just using a native local filesystem, > though. Taking away all of that memory that FreeBSD would otherwise > use for *caching* file data could well end up making your builds > *slower* with the MFS than they would have been without it. I've a vague recollection that I tried something like this, a few years ago, and found that the difference was too small to measure. I think that however you do it, you basically end-up with something that looks like: CPU/L1/L2 -> memory -> disk and whether the "memory->disk" part is a cached-file or swap-backed memory is really just a matter of book-keeping - the VM system moves the physical memory around as it likes. The book-keeping differences may be significant, but they are not different in the electronic verses electro-mechanical sense, and such intuitions may not relevant. Poul-Henning Kamp, has an interesting article in this area for the varnish project: "I have spent many years working on the FreeBSD kernel, and only rarely did I venture into userland programming, but when I had occation to do so, I invariably found that people programmed like it was still 1975." http://varnish.projects.linpro.no/wiki/ArchitectNotes [Not that there's anything wrong with 1975.] _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
