From owner-freebsd-arm@freebsd.org Sat Mar 18 18:03:47 2017 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E91A9D12555 for ; Sat, 18 Mar 2017 18:03:47 +0000 (UTC) (envelope-from rj@obsigna.com) Received: from mo6-p00-ob.smtp.rzone.de (mo6-p00-ob.smtp.rzone.de [IPv6:2a01:238:20a:202:5300::7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.smtp.rzone.de", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8743E104B for ; Sat, 18 Mar 2017 18:03:47 +0000 (UTC) (envelope-from rj@obsigna.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1489860224; l=3053; s=domk; d=obsigna.com; h=To:References:Content-Transfer-Encoding:Date:In-Reply-To:From: Subject:Mime-Version:Content-Type; bh=dnN0PVwJ/knyVQoyvkMavm7VKbmJbAw4fG55K4UcIjU=; b=DlTWh95D8fZUmLpojHEiecMf+WrG2REBKpB3pcuQ9Xec5LJ08aGh8RHdy0bF/eUl6b 4fRfiljUaIeoPBxr4nHLEGZD4ibI4JIj89Ho7uZ5/j4Solz28FtvFc51TJ/nDVvCfBoN /i0K/HIx4Es8FLvBcY/eRrf20zH7Wy4dq7ZlE= X-RZG-AUTH: :O2kGeEG7b/pS1EK7WHa0hxqKZr4lnx6UhT0M0o35iAdWtoM07Gt3wQHFGh0n99Hk6LY= X-RZG-CLASS-ID: mo00 Received: from mail.obsigna.com (bb02b8ae.virtua.com.br [187.2.184.174]) by smtp.strato.de (RZmta 40.1 DYNA|AUTH) with ESMTPSA id j04813t2II3hBzD (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate) for ; Sat, 18 Mar 2017 19:03:43 +0100 (CET) Received: from rolf.projectworld.net (rolf.projectworld.net [192.168.222.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.obsigna.com (Postfix) with ESMTPSA id 457587506DAD for ; Sat, 18 Mar 2017 15:03:40 -0300 (BRT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: Identifying counterfeit microSD cards on a Beaglebone Black From: "Dr. Rolf Jansen" In-Reply-To: Date: Sat, 18 Mar 2017 15:03:38 -0300 Content-Transfer-Encoding: quoted-printable Message-Id: References: To: freebsd-arm@freebsd.org X-Mailer: Apple Mail (2.1878.6) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 Mar 2017 18:03:48 -0000 Am 18.03.2017 um 12:30 schrieb Warner Losh : > On Sat, Mar 18, 2017 at 8:44 AM, Dr. Rolf Jansen = wrote: >> I bought a 16 GB microSDHC SanDisk chip rated at 4 MB/s write speed = for use with my Beaglebone Black. >>=20 >> The internal flash offers practical write speeds in the range of 2 to = 3 MB/s when copying data to it from a NFSv4 volume depending on the size = of the files being copied. Executing the same copy operation with said = microSDHC card as the target I see only 0.1 to 0.2 MB/s (less than = 1/10). >>=20 >> I suspect now that I got a counterfeited card. Before I dump it, I = would like to run a definitive non-destructive test, preferably on the = Beaglebone Black, and I would like to ask you for suggestions. >>=20 >> Also, it would be nice to see some speed values as a reference for = microSDHC card write speeds on: >>=20 >> FreeBSD 12.0-CURRENT (BEAGLEBONE) #0 r315413 >>=20 >> Many thanks in advance for any help. >=20 > Copy a huge file from /dev/zero. Smaller files in the filesystem > generate a lot of overhead and 'wait points' that slow down overall > performance. >=20 > Or better yet, dd to the raw device. /dev/random should generate data > faster than the card can handle. Depends on what you mean by > 'non-destructive' >=20 > And all NAND sucks. It's a pig with lipstick on it. So you won't get > even performance if the FTL in the SD card sucks. Garbage collection, > internal house keeping, etc all can steal performance from the user > application. These cards are generally designed to take a burst of > writes when the camera or video is taken, then have it read back > later. A mixed workload was never optimized for on most of these > cards, so it can also significantly degrade performance even at low > percentage mixtures. >=20 > So all those things could be going on w/o it being a counterfeit. :(. > Of course, it could have all those things going on and also be a > counterfeit. Hard to say for sure unless the performance is wildly > different. But 4MB/s write performance is pretty pathetic for a card > of that size, so it's on the low end, which suffers most from uneven > performance and "down hill with the wind" spec numbers. Warner, thank you very much for taking your time responding. It is a Class 4 card, i.e. guaranteed minimum write speed should be 4 = MB/s, and I know the difference between advertised and practical speed, = I would have expected at lest 50 % of the advertised speed, i.e. = something in the range that can be achieved with the internal flash of = the BBB. I would even be happy if it would come close to 1 MB/s. But 0.1 = MB/s that is a quit huge difference -- 40 times less than the advertised = speed. You said, that 4 MB/s is "pretty pathetic". Therefore let me ask a = different question. What is the best write speed that can be achieved = with what model of a microSD card on a Beaglebone Black running FreeBSD = 12-Current? Many thanks and best regards Rolf