From owner-freebsd-threads@FreeBSD.ORG Sat Nov 29 16:54:21 2003 Return-Path: Delivered-To: freebsd-threads@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4353616A4CE for ; Sat, 29 Nov 2003 16:54:21 -0800 (PST) Received: from maxwell.syr.edu (maxwell.syr.edu [128.230.129.5]) by mx1.FreeBSD.org (Postfix) with ESMTP id 047B743FE1 for ; Sat, 29 Nov 2003 16:54:20 -0800 (PST) (envelope-from cmsedore@maxwell.syr.edu) Received: from exchange.maxwell.syr.edu (excluster2.maxwell.syr.edu [128.230.129.231]) by maxwell.syr.edu (8.12.10/8.9.1) with ESMTP id hAU0sHo2074226 for ; Sat, 29 Nov 2003 19:54:17 -0500 (EST) X-MIMEOLE: Produced By Microsoft Exchange V6.5.6944.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Date: Sat, 29 Nov 2003 19:54:19 -0500 Message-ID: <32A8B2CB12BFC84D8D11D872C787AA9A515DAE@EXCHANGE.forest.maxwell.syr.edu> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: KSE system scope vs non system scope threads Thread-Index: AcO23HxUZwzU2dUpSUOH+aMSi7ZkFw== From: "Christopher M. Sedore" To: Subject: KSE system scope vs non system scope threads X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Nov 2003 00:54:21 -0000 =20 I have a fairly simple question about KSE threads: In a threaded program = using KSE threads, what is the effective difference between a = system-scope thread and a non-system-scope thread? If I understand the = KSE architecture correctly, there should not be a significant functional = difference. If my reading lead me to the right conclusion, at the = nitty-gritty level, there are multiple KSE groups created with = system-scope threads, as I understand it, meaning that the kernel = scheduler actually does the scheduling work for system-scope threads, = instead of the userland KSE scheduler. =20 I ask this because I'm observing some behavior that I don't expect. = When running a threaded program with KSE and non-system-scope threads, I = see performance degradation in my network traffic when I'm attempting to = connect to remote hosts that are down. Libthr doesn't see this = degradation, and KSE with system-scope threads doesn't perform as well = as libthr, but is much closer. =20 If there is a canonical document that describes all this, a pointer = would be very welcome. =20 -Chris