From owner-freebsd-hackers Wed May 17 9:52:33 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from fw.wintelcom.net (ns1.wintelcom.net [209.1.153.20]) by hub.freebsd.org (Postfix) with ESMTP id 00E6237B9A2 for ; Wed, 17 May 2000 09:52:25 -0700 (PDT) (envelope-from bright@fw.wintelcom.net) Received: (from bright@localhost) by fw.wintelcom.net (8.10.0/8.10.0) id e4HHPHZ15074; Wed, 17 May 2000 10:25:17 -0700 (PDT) Date: Wed, 17 May 2000 10:25:16 -0700 From: Alfred Perlstein To: Joy Ganguly Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Question about file write???? Message-ID: <20000517102516.B14968@fw.wintelcom.net> References: <20000517160746.12768.qmail@www0a.netaddress.usa.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0.1i In-Reply-To: <20000517160746.12768.qmail@www0a.netaddress.usa.net>; from joy.ganguly@usa.net on Wed, May 17, 2000 at 10:07:46AM -0600 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG * Joy Ganguly [000517 09:41] wrote: > > hi all, > > i have written a special ioctl which writes data into a file from a buffer in > kernel memory. it invokes fo->fo_write() and involves one copy from kernel > mem > to disk cache. however this takes substantially more time than an ordinary > write which copies from user space to the disk cache. any explanations??? What are you using for your kernel to kernel copy? (copyin and friends are hand optimized for great speed when copying from/to userspace) -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message