From owner-freebsd-hackers@FreeBSD.ORG Tue Oct 12 20:34:04 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 54E3910656B1 for ; Tue, 12 Oct 2010 20:34:04 +0000 (UTC) (envelope-from yanegomi@gmail.com) Received: from mail-gy0-f182.google.com (mail-gy0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id 09B1D8FC1C for ; Tue, 12 Oct 2010 20:34:03 +0000 (UTC) Received: by gyf3 with SMTP id 3so1344591gyf.13 for ; Tue, 12 Oct 2010 13:34:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type; bh=dis/EaE0O4DF+W2WxQ9x7Jeoy2PyIi89Aed9mOVVccI=; b=smx1siD0PBsZTHwgivIsdHzOKQYHBdY163os6LA460r0zDvdH6njjtmrRnyy0CChTh z9+VtwZtVT757e3wr27gHYACp/UJRmzCdxlN7EEb2tWR0kC2MoTbMk/5LZzc5cUktAez EebxjCOPkr29VtDZkiAiCsWC53U5fBOYcyJJc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; b=MUWAaurxCnFsbrVfMPShGQT0ZU+Rc7c4XgQQlebV534U8yEC1Pd6Zb/LW2G/aoLQzU KmfmSf8YtaC+2w4XSyyKOnrKexNl+uX4KE7QJdCd9iH2CW0SQBfaXw8IAJtsQ6yCpkVa IdfaLmYgDxkh3M4kUCLHCrcIMP5cm/Vhv8/0U= MIME-Version: 1.0 Received: by 10.90.73.9 with SMTP id v9mr3860194aga.89.1286915642947; Tue, 12 Oct 2010 13:34:02 -0700 (PDT) Sender: yanegomi@gmail.com Received: by 10.90.109.16 with HTTP; Tue, 12 Oct 2010 13:34:02 -0700 (PDT) In-Reply-To: References: Date: Tue, 12 Oct 2010 13:34:02 -0700 X-Google-Sender-Auth: vjs5CFvIeavL0Rxu86fNWV5fVNI Message-ID: From: Garrett Cooper To: Eknath Venkataramani Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-hackers@freebsd.org Subject: Re: Scheduler Question X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Oct 2010 20:34:04 -0000 On Sat, Oct 9, 2010 at 4:46 PM, Eknath Venkataramani wrote: > D&I of the FreeBSD Operating System says it's gonna refer to the BSD default > scheduler, the 'time share scheduler' does this mean sched_4BSD.c(In the > introduction section of Chapter 4) handles only time-share process? > If so, then how (or where) are the kernel processes/real time process > scheduled? The Design and Implementation of the FreeBSD Operating System is unfortunately extremely out of date (my edition which I think is the latest one refers to FreeBSD 5.2). The FreeBSD scheduler was switched over to sched_ule.c as the default scheduler in 7.1. So I'd invest more time in determining how SCHED_ULE works rather than SCHED_4BSD going forward (even though learning about SCHED_4BSD is a good lesson in history of design of FreeBSD). FWIW the algorithm of prioritization, quantization of time slices, etc for SCHED_4BSD are discussed more in depth in the chapter. Cheers, -Garrett