From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.fusionio.com ([66.114.96.31]:49608 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751062Ab2G0LIi (ORCPT ); Fri, 27 Jul 2012 07:08:38 -0400 Date: Fri, 27 Jul 2012 07:08:35 -0400 From: Chris Mason To: Marc MERLIN CC: "linux-btrfs@vger.kernel.org" Subject: Re: How can btrfs take 23sec to stat 23K files from an SSD? Message-ID: <20120727110835.GA6933@shiny> References: <20120718220446.GB3888@merlins.org> <20120722185848.GA10089@merlins.org> <201207222135.11159.Martin@lichtvoll.de> <20120202124241.GW16796@shiny> <20120718220446.GB3888@merlins.org> <20120722185848.GA10089@merlins.org> <201207222135.11159.Martin@lichtvoll.de> <20120722204428.GC3925@merlins.org> <20120722224145.GC12951@merlins.org> <20120723064202.GB6931@merlins.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <20120723064202.GB6931@merlins.org> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Jul 23, 2012 at 12:42:03AM -0600, Marc MERLIN wrote: > > 22 seconds for 15K files on an SSD is super slow and being 5 times > slower than a spinning disk with the same data. > What's going on? Hi Marc, The easiest way to figure out is with latencytop. I'd either run the latencytop gui or use the latencytop -c patch which sends a text dump to the console. This is assuming that you're not pegged at 100% CPU... https://oss.oracle.com/~mason/latencytop.patch -chris