From owner-freebsd-arm@FreeBSD.ORG Fri Jan 3 06:19:50 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 0B12B719 for ; Fri, 3 Jan 2014 06:19:50 +0000 (UTC) Received: from mail-ie0-f180.google.com (mail-ie0-f180.google.com [209.85.223.180]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id C90FB1C8B for ; Fri, 3 Jan 2014 06:19:49 +0000 (UTC) Received: by mail-ie0-f180.google.com with SMTP id tp5so15002869ieb.25 for ; Thu, 02 Jan 2014 22:19:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=H5ymLTyG2GUT8Lymz9NfaOkXpCC8r2b6ysxcHSrRZ50=; b=fHcGNc4DrEIksWIXldPwMehagE9tFpqwob9K+GGNxBbVhB/c5mFVx5uDlR4h+xG7q+ bUcdTgzsjkaN/X5MPC5h8BhxF23CPE8fU0ij9nHRPR0v8dZf2A4huY1abYHhy4HsOYIZ FkIoVjbB4161WNEfoI88PV3KuAnllmH4Zodj7C+hyrXt7UR5K3tj1nQ4trrwXWfSKMbA XWTMsyaAnAsM4KahaJDcqKLlfeHy9YrFw++aA7pdxyFvAFNU7f8t1iI+FOXlapdETNm7 tq3t/h/V8Kh/zUCKXpHwvnwaqXR2UV0KHdR/TzZhhd94SMSPw7zRfKISxixhUAB0stAI n1fw== X-Gm-Message-State: ALoCoQnH4bqJaLRG2o5ieUQ+2I0uHgBPpmU1cpkgfhxBjfWGsm4HuEeaDoBhY8fQOAURn0CJcyyw X-Received: by 10.43.49.132 with SMTP id va4mr3007icb.79.1388729615921; Thu, 02 Jan 2014 22:13:35 -0800 (PST) Received: from [10.0.0.23] (50-78-194-198-static.hfc.comcastbusiness.net. [50.78.194.198]) by mx.google.com with ESMTPSA id da14sm887442igc.1.2014.01.02.22.13.35 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 02 Jan 2014 22:13:35 -0800 (PST) Sender: Warner Losh Subject: Re: Beagle recommendations Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Warner Losh In-Reply-To: <20140103052201.E9397200F5@smtp.hushmail.com> Date: Thu, 2 Jan 2014 23:13:32 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20140103052201.E9397200F5@smtp.hushmail.com> To: chump1@hushmail.com X-Mailer: Apple Mail (2.1085) Cc: freebsd-arm@freebsd.org X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Jan 2014 06:19:50 -0000 Do you have options SMP in your kernel? Warner On Jan 2, 2014, at 10:22 PM, chump1@hushmail.com wrote: >=20 > I have a fairly simple task that involves processing something in a 2D = array, MxN times. I took a naive approach, 1x process 1x thread, and it = took a little longer than desired. Well now, I could do better with some = multi processing, especially on a multi core box, right? >=20 >=20 >=20 >=20 > Well, I have not had much luck. At first I spawned M threads and had = each iterate over each N in turn, with M between 25-35. It took much, = much longer than the single thread. I figured contention and overhead = were costing me big, and gave it a shot with a scaled down version of = the problem, M=3D10. Still, much slower than the single thread. A little = confused, I went back to the big problem set (25-35), and made a new = program that spawned only two threads, and each is limited to processing = only even or only odd data sets. Even that still takes twice as long as = the single thread version! What is up with that? >=20 >=20 >=20 >=20 > More important asides, I am barely doing any real processing at all. = It is basically a no-op, barely doing more than incrementing the = counter. Should I expect to see performance gains once I am doing real = work in the processing portion of my program? Should I expect to see = much different behavior on a different OS? Also I have one physical = processor, two cores. Would I see better gains with more cores? How do = you find processes and threads scale against hardware overall? >=20 >=20 >=20 >=20 > Thanks! >=20 >=20 > Sent using Hushmail >=20 > _______________________________________________ > freebsd-arm@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"