Path: utzoo!utgpu!jarvis.csri.toronto.edu!white.toronto.edu!cks Newsgroups: comp.unix.wizards From: cks@white.toronto.edu (Chris Siebenmann) Subject: Re: filenames and the kernel Message-ID: <1990Feb2.162828.214@jarvis.csri.toronto.edu> Organization: Ziebmef home away from home References: <22167@adm.BRL.MIL> <:V91RE7xds13@ficc.uu.net> <23580@stealth.acf.nyu.edu> Date: 2 Feb 90 21:28:29 GMT Lines: 19 One good reason to keep namei()'s functionality in the kernel is that old boogy-man, effeciency. Local figures show that the kernel spends about 25% of its time in namei(), and between 25% and 50% (the percentage goes down as the load goes up) of the block reads done on typical systems are done by namei() -- and this doesn't count symlink reads done during name resolution (appallingly common on our Ultrix systems). A efficient system with namei() in user space might not look very Unix-like internally; I'd expect it to have good, fast kernel<->user process and user<->user communication methods (perhaps based on remapping VM pages) and a very fast context switch. [A reminder: please avoid casual use of "usa" distribution; otherwise, many interested people will never see your article.] -- "I shall clasp my hands together and bow to the corners of the world." Number Ten Ox, "Bridge of Birds" cks@white.toronto.edu ...!{utgpu,utzoo,watmath}!utcsri!white!cks