From owner-freebsd-fs@freebsd.org Fri Feb 19 18:08:48 2016 Return-Path: Delivered-To: freebsd-fs@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 AA9ADAAE2B9 for ; Fri, 19 Feb 2016 18:08:48 +0000 (UTC) (envelope-from mwlucas@mail.michaelwlucas.com) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 9696E1142 for ; Fri, 19 Feb 2016 18:08:48 +0000 (UTC) (envelope-from mwlucas@mail.michaelwlucas.com) Received: by mailman.ysv.freebsd.org (Postfix) id 93CBDAAE2B8; Fri, 19 Feb 2016 18:08:48 +0000 (UTC) Delivered-To: fs@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 9364CAAE2B7 for ; Fri, 19 Feb 2016 18:08:48 +0000 (UTC) (envelope-from mwlucas@mail.michaelwlucas.com) Received: from mail.michaelwlucas.com (mail.michaelwlucas.com [104.236.197.233]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 3B9651141 for ; Fri, 19 Feb 2016 18:08:47 +0000 (UTC) (envelope-from mwlucas@mail.michaelwlucas.com) Received: from mail.michaelwlucas.com (localhost [127.0.0.1]) by mail.michaelwlucas.com (8.15.2/8.15.2) with ESMTP id u1JI7H5e046977 for ; Fri, 19 Feb 2016 13:07:21 -0500 (EST) (envelope-from mwlucas@mail.michaelwlucas.com) Received: (from mwlucas@localhost) by mail.michaelwlucas.com (8.15.2/8.15.2/Submit) id u1JI7Gc6046976 for fs@freebsd.org; Fri, 19 Feb 2016 13:07:16 -0500 (EST) (envelope-from mwlucas) Date: Fri, 19 Feb 2016 13:07:16 -0500 From: "Michael W. Lucas" To: fs@freebsd.org Subject: dtracing ZFS on FreeBSD Message-ID: <20160219180716.GA46881@mail.michaelwlucas.com> MIME-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.5.24 (2015-08-30) X-Spam-Status: No, score=0.0 required=5.0 tests=UNPARSEABLE_RELAY, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on mail.michaelwlucas.com X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (mail.michaelwlucas.com [127.0.0.1]); Fri, 19 Feb 2016 13:07:26 -0500 (EST) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2016 18:08:48 -0000 Hi, I'm trying get Adam Leventhal's dtrace script for measuring latency and number of operations on a pool (http://dtrace.org/blogs/ahl/2014/08/31/openzfs-tuning/). Asking for guidance here because it's a filesystem thing and the dtrace list is dead. The script is: #pragma D option aggpack #pragma D option quiet fbt::vdev_queue_max_async_writes:entry { self->spa = args[0]; } fbt::vdev_queue_max_async_writes:return /self->spa && self->spa->spa_name == $$1/ { @ = lquantize(args[1], 0, 30, 1); } tick-1s { printa(@); clear(@); } fbt::vdev_queue_max_async_writes:return /self->spa/ { self->spa = 0; } When I run it: # dtrace -s q.d zroot most lines look like this: min .--------------------------------. max | count < 0 : : >= 30 | 0 dtrace: 15857 dynamic variable drops with non-empty dirty list My reading of dtrace discussions says I'm losing data here. I suspect this is the data I'm actually interested in. Sometimes, the scale gets a marker on it. Pardon the weird characters: min .--------------------------------. max | count < 0 : █ : >= 30 | 3438 Or there's min .--------------------------------. max | count < 0 : ▁▂▃▅ : >= 30 | 19172 Any thoughts on why? Thanks, ==ml -- Michael W. Lucas - mwlucas@michaelwlucas.com, Twitter @mwlauthor http://www.MichaelWLucas.com/, http://blather.MichaelWLucas.com/