From owner-svn-src-head@freebsd.org Fri Oct 16 19:16:50 2015 Return-Path: Delivered-To: svn-src-head@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 A7450A167B2 for ; Fri, 16 Oct 2015 19:16:50 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7C7911B89 for ; Fri, 16 Oct 2015 19:16:50 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: by pacez2 with SMTP id ez2so12348240pac.1 for ; Fri, 16 Oct 2015 12:16:43 -0700 (PDT) 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:message-id:references:to; bh=C0Di2Rpc5cr7PhSWee3fFGHWnY3qlKZgCtMh5fhC+Ds=; b=OwOoWzm/41BITNL6TYnQm9dfBavbr7xRg0Q9pGd4KNJO+0x90ljQ5SvxpgnqJo1aYH 31sIsh+D6vGXjO5GGirIlyy2bECNXdQG1N+cpd71Nyqb5gwAm1kyvmBOLdcbwnxjgZPp bGfbwXV+TRqO3Ehigoam3bZ8ubb6HYY4o/8uy8xdflW3QY+5eVUSdcOSqT6GE+ZntVBk 4BF2+GbmE6c8BuIiZivUrXZG6vtWLHPXoXXQ5uHO7YPXPGrUb/tP5J9c8GzdBPrM+DSr Mw0xCcAHALQWvDMAMOtPyj8OPkcsDa7VoveG7+LrWgpx9x1j8ie7FiYKfPvX1ZllKpd2 TlgQ== X-Gm-Message-State: ALoCoQnm7tHs9ab86y1iruQPFKu7bT4afNBj9/vYjGsNvn+fKOeBClzAubWXHcwXpxN/5CYNaMRL X-Received: by 10.66.253.99 with SMTP id zz3mr18136324pac.38.1445023003857; Fri, 16 Oct 2015 12:16:43 -0700 (PDT) Received: from ip-100-127-144-209.ec2.internal ([69.53.245.40]) by smtp.gmail.com with ESMTPSA id w8sm22582800pbs.87.2015.10.16.12.16.42 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 16 Oct 2015 12:16:43 -0700 (PDT) Sender: Warner Losh Subject: Re: svn commit: r289405 - head/sys/ufs/ffs Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Content-Type: multipart/signed; boundary="Apple-Mail=_F5C7F81A-87C9-4B9F-AF3C-C309D07FE444"; protocol="application/pgp-signature"; micalg=pgp-sha512 X-Pgp-Agent: GPGMail 2.5.2 From: Warner Losh In-Reply-To: <5620B15C.8090104@selasky.org> Date: Fri, 16 Oct 2015 13:16:39 -0600 Cc: Bruce Evans , Warner Losh , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Message-Id: References: <201510160306.t9G3622O049128@repo.freebsd.org> <20151016151349.W1280@besplex.bde.org> <5620B15C.8090104@selasky.org> To: Hans Petter Selasky X-Mailer: Apple Mail (2.2104) X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Oct 2015 19:16:50 -0000 --Apple-Mail=_F5C7F81A-87C9-4B9F-AF3C-C309D07FE444 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 > On Oct 16, 2015, at 2:12 AM, Hans Petter Selasky = wrote: >=20 > On 10/16/15 08:21, Bruce Evans wrote: >> In addition, making the file contiguous in LBA space doesn't >> improve the access times from flash devices because they have no = seek >> time. >=20 > Hi, >=20 > This is not exactly true, like Bruce pointed out too. Maybe there = should be a check, that if the block is too small reallocate it, else = leave it for the sake of the flash. Doing 1K accesses versus 64K = accesses will typically show up in the performance benchmark regardless = of how fast the underlying medium is. But that=92s not what this does. It isn=92t the defrag code that takes = the 2-8k fragments and squashes them into 16-64k block size for the = device. This takes the larger blocks and makes sure they are next to = each other. This takes large contiguous space (like 2MB) and puts as = much as possible in a cylinder group. That=92s totally useless on a = flash drive. Since the sizes of the blocks are so large, moving them won=92t change = any benchmarks. Warner --Apple-Mail=_F5C7F81A-87C9-4B9F-AF3C-C309D07FE444 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWIU0XAAoJEGwc0Sh9sBEA2NAP/jExMKGTXDjVBkUPfavVpXSY cUdIspM7IEasio9YevjdT17MePqRGd5Iwc8ViYvZC2RwACUMYbjKl2fP02DxJfd2 BafqkQB+Ruxpgggj8YpV0J9o2vcagmehr9waX47DvlpQ+r1XnltmpK94xU3FP81F 4V2/7Cqqx0AA20yOD3dorEvZYEfV6w4fv1j0AqanXXzNOJ3uOY4G7XhTbDPr8eGg eOLeqocZ7ssN+Gms0VA8mUAK5nKld47bOJPM3M3+x3Q+GRxVQ0ojNQKHh8hBUlRN cLGL5SW0wTF4VpHAEx5MaC8YoWMhIvbFcf+rmFDTgfkeomE2eVSo5OdjbTQmdS/t yRGzjpRe/o20BSn0xURzkqwiIMKhoTzBeDOhyBP3WAmCy5P3JGsMCErsxTp3g0AM zEnA7d0AX79WfLxO+ybZyRFACO1W1N+0inlbB0QSouxIgqC85OJ2eohvQwexso1E MP+ZYpJXqiDsiEgt9r8Xy57yUbmS6Nyo5kkn6EutGozV+aQlZhgKaZtQl6KC7/1x fYvI4CFywfB/aVUQznaY3PGlDwd3123djNATTAI+z/dwX1P4R0elf2TfYlax0CBx aGY3PeExVZeclKD1eHYi/3ZlD37dzRs8Z7CZzd5OlXRHfvMZOMDi/lxswJZ2VcUh /UZAVvTW/OQ56aSejQhG =t5ja -----END PGP SIGNATURE----- --Apple-Mail=_F5C7F81A-87C9-4B9F-AF3C-C309D07FE444--