From owner-freebsd-hackers Tue Apr 14 11:31:53 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA05572 for freebsd-hackers-outgoing; Tue, 14 Apr 1998 11:31:53 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from asteroid.svib.ru (root@asteroid.svib.ru [195.151.166.145]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id SAA05539; Tue, 14 Apr 1998 18:31:44 GMT (envelope-from tarkhil@asteroid.svib.ru) Received: from minas-tirith.pol.ru (shuttle.svib.ru [195.151.166.144]) by asteroid.svib.ru (8.8.8/8.8.8) with ESMTP id WAA20945; Tue, 14 Apr 1998 22:31:34 +0400 (MSD) (envelope-from tarkhil@asteroid.svib.ru) Received: from minas-tirith.pol.ru (minas-tirith.pol.ru [127.0.0.1]) by minas-tirith.pol.ru (8.8.8/8.8.7) with ESMTP id WAA15886; Tue, 14 Apr 1998 22:31:26 +0400 (MSD) (envelope-from tarkhil@minas-tirith.pol.ru) Message-Id: <199804141831.WAA15886@minas-tirith.pol.ru> X-Mailer: exmh version 2.0.1 12/23/97 To: Frank Ederveen cc: hackers@FreeBSD.ORG, smp@FreeBSD.ORG Subject: Re: SMP performance decrease? In-reply-to: Your message "Tue, 14 Apr 1998 16:59:40 +0200." <19980414165940.06093@domaintje.com> Reply-To: tarkhil@asteroid.svib.ru Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Tue, 14 Apr 1998 22:31:22 +0400 From: Alex Povolotsky Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG <19980414165940.06093@domaintje.com>Frank Ederveen writes: >> Execl thoughput 90.8 46.8 <- ??? >> Pipe-based context switching 20.4 9.0 <- ??? >> Shell scripts (8 concurrent) 12.8 12.2 <- ??? >> I don't understand why execl throughput and context switching is TWICE >> slower in SMP mode, and I doesn't understand AT ALL why shell script >> benchmark isn't twice faster. >I don't know Benchbyte, but maybe these are times in seconds and >lower is better? Also, unless you have an automatic multi threading No :-( >compiler like Convex has the second cpu doesn't do you much good >if you only run one process in your benchmark. Well, I can beleive if performance won't increase. But why can it DECREASE? Alex. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message