From owner-freebsd-hackers Tue Dec 17 13:51:20 1996 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id NAA21747 for hackers-outgoing; Tue, 17 Dec 1996 13:51:20 -0800 (PST) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id NAA21707; Tue, 17 Dec 1996 13:50:29 -0800 (PST) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id OAA08978; Tue, 17 Dec 1996 14:48:58 -0700 From: Terry Lambert Message-Id: <199612172148.OAA08978@phaeton.artisoft.com> Subject: Re: Almost have mmap() figured, I think... To: dyson@freebsd.org Date: Tue, 17 Dec 1996 14:48:58 -0700 (MST) Cc: terry@lambert.org, scrappy@hub.org, hackers@freebsd.org In-Reply-To: <199612172119.QAA05589@dyson.iquest.net> from "John Dyson" at Dec 17, 96 04:19:17 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > The Stevens book is the bible... but that example you might want to > > consider most relevent is in the cp code in /src/bin/cp/utils.c. > > > > John: there is still "#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED" in that > > code... is that right now? > > The ifdef can go away now -- no problem. The problem is a performance > issue where copying a large file will cause lots of memory usage... The > buffer cache is better tuned for file I/O. Any chance of per vnode working set restrictions? They would be easy to implement by keeping a page count and changing lru insertion order over the count, it seems to me. The SVR4 ld thrashed the cache by mmap'ing a bunch of files; the UnixWare folks seems to head off into the weeds at that point, including coming up with an entirely new scheduling class for their X server to fix the "move mouse, wiggle cursor" problem cause by it swapping the whole X server out while servicing the ld. A trivial working set restriction (no LRU on a per vnode basis) cleaned it right up without needing new scheduling classes and all that crap that they had added. 8-(. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.