From owner-freebsd-hackers@FreeBSD.ORG Tue Jan 18 16:10:29 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4BEB516A4CF for ; Tue, 18 Jan 2005 16:10:29 +0000 (GMT) Received: from smtpout-2.priv.cc.uic.edu (smtpout-2.cc.uic.edu [128.248.155.233]) by mx1.FreeBSD.org (Postfix) with SMTP id C2BCD43D1F for ; Tue, 18 Jan 2005 16:10:09 +0000 (GMT) (envelope-from zholla1@uic.edu) Received: (qmail 32617 invoked from network); 18 Jan 2005 10:10:09 -0600 Received: from icarus.cc.uic.edu (128.248.155.80) by smtpout-2.cc.uic.edu with SMTP; 18 Jan 2005 10:10:09 -0600 Date: Tue, 18 Jan 2005 10:10:09 -0600 (CST) From: Zera William Holladay X-X-Sender: zholla1@icarus.cc.uic.edu To: freebsd-hackers@freebsd.org In-Reply-To: <20050118140523.GE3054@empiric.icir.org> Message-ID: References: <002201c4fd4a$c5a81230$0700a8c0@felix> <20050118140523.GE3054@empiric.icir.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Subject: Re: Kernel mode programming X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Jan 2005 16:10:29 -0000 On Tue, 18 Jan 2005, Bruce M Simpson wrote: > On Tue, Jan 18, 2005 at 11:45:05AM +0100, - Felix - wrote: > > Doing lot of syscalls interrupts in a soft seems to take quite a long time, and seriously slow performances. As far as you can't reduce the syscall amount, is there any way to run apps in kernel mode, in order to call sysfonctions directly ? Perhaps by re-writing softs in kernel modules ? > > For 95% of applications syscall overhead shouldn't have a major impact on > performance. It's difficult to offer any real advice here because you haven't > said what the application is, or shown any profiling figures. Even if the application were run as a kernel module, how much of a performance benefit could there be when making system calls? I suspect that the module would get a higher scheduling priority but realistically wouldn't the module still have to make system calls in the same manner that a regular user process does? I really don't know, so would some kind soul tell me please? -Zera Holladay