From owner-freebsd-current@FreeBSD.ORG Sun Nov 16 02:26:23 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id DBC1ADD for ; Sun, 16 Nov 2014 02:26:23 +0000 (UTC) Received: from mail-pa0-x22e.google.com (mail-pa0-x22e.google.com [IPv6:2607:f8b0:400e:c03::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A3D6D7E1 for ; Sun, 16 Nov 2014 02:26:23 +0000 (UTC) Received: by mail-pa0-f46.google.com with SMTP id lf10so19874707pab.19 for ; Sat, 15 Nov 2014 18:26:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=m7oYquO38ulUQ78TGtisS9YrYGZeHP481brF0pyPnEU=; b=FjF2XWiMol/0WKhQXG5x8UzEeU1D6yttfu5NEF3BQtqZbRIjC3k70fpd2/qWSsdi9q X/1z8ut+vmgs7j8ttflkwwIv/LgkfraGERhStwtxStA5shduT/1Qu71yOuaT/vhLU/MH 3KvDMu/JY0lqtGlaDXFFta+tMbQ5YS9fr7zo+P0Wgv/p2d4B/ORXtzIXW3V6BMAqP1Hn RlsReMLoLkKuqrBVe0QrQaMmWgdMIOW4CLWSpk9fKKE9myrZQFkAB5AxvWRMXpyHnM+/ 290aqmXsP+uu6fmVQljNy/ptr0zo2eimov7OY92hzetjM5a1RGE6rOaihRc7V1aHg6Lz EKKg== X-Received: by 10.70.138.104 with SMTP id qp8mr19719949pdb.99.1416104783171; Sat, 15 Nov 2014 18:26:23 -0800 (PST) Received: from mavbook.mavhome.dp.ua ([97.84.68.201]) by mx.google.com with ESMTPSA id bf2sm31343638pbb.13.2014.11.15.18.26.21 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 15 Nov 2014 18:26:22 -0800 (PST) Sender: Alexander Motin Message-ID: <54680B4C.9020207@FreeBSD.org> Date: Sun, 16 Nov 2014 04:26:20 +0200 From: Alexander Motin User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Garrett Cooper , "Ranjan1018 ." <214748mv@gmail.com> Subject: Re: [PATCH] gstat on SSD References: <1263A474-E3B8-4942-A0AA-6692F509138F@gmail.com> In-Reply-To: <1263A474-E3B8-4942-A0AA-6692F509138F@gmail.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: FreeBSD CURRENT X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 Nov 2014 02:26:24 -0000 On 15.11.2014 23:35, Garrett Cooper wrote: > On Nov 15, 2014, at 8:04, Ranjan1018 . <214748mv@gmail.com> wrote: >> I am running a pair of servers with SSD. In gstat the default >> display of operation/ms is only one digit after the comma and >> there are a lot of R/W operation displayed with the 0.1 value. >> This simple patch displays the operation/ms with two decimal >> digit. >> >> What’s next ? After testing this patch for a day, recording the >> values in a log file, I have found that some write operation are >> only 0.02 ms short, on a OCZ Vertex SSD. Probably the next patch >> is to display micro seconds instead of milli seconds. >> >> Maurizio >> >> FreeBSD 11 gstat.c.patch > > LGTM, but I don’t have hardware capable of that precision so I > can’t verify the patch other than build test it and run it for what > existing cases I have. > > What do you think Alexander? SSD in my laptop can to 20K simple case IOPS in one stream, that means ~50us time. So I think this patch should not harm. From the other side these numbers are mostly informational, since any real performance investigation would require a histogram rather the a single average number. -- Alexander Motin