From owner-freebsd-current@freebsd.org Wed Apr 25 00:22:23 2018 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1900CFB86B7 for ; Wed, 25 Apr 2018 00:22:23 +0000 (UTC) (envelope-from greg@unrelenting.technology) Received: from hraggstad.unrelenting.technology (hraggstad.unrelenting.technology [71.19.146.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hraggstad.unrelenting.technology", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8619587715; Wed, 25 Apr 2018 00:22:22 +0000 (UTC) (envelope-from greg@unrelenting.technology) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=unrelenting.technology; h=date:from:subject:to:message-id; s=default; bh=NWZv8IUlNj0DKWUMH7nxS1UFhbgtZPqR8z2Pk992F6I=; b=AkxJ+NOjDm1HNdBdPkQpbjtYGni6qmwWH1Ml89fSooyBh2fz8r5UO9Qz6Z8diJXEAdUg4nsNX086zjErSsWBmtylFwzHi1F6/P0SH1QDMFIfwLslc6qfW7plPS9TZp+wzsQuCJmO3QEK5d5iFRzATzCuqKkhW0EdjCLY/H9lpyM= Received: by hraggstad.unrelenting.technology (OpenSMTPD) with ESMTPSA id 60892eb4 TLS version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO; Wed, 25 Apr 2018 00:15:38 +0000 (UTC) Date: Wed, 25 Apr 2018 03:15:33 +0300 From: Greg V Subject: Re: zfskern{txg_thread_enter} thread using 100% or more CPU To: Steve Wills Cc: FreeBSD Current Message-Id: <1524615333.3550.1@hraggstad.unrelenting.technology> In-Reply-To: References: X-Mailer: geary/0.12.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.25 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: Wed, 25 Apr 2018 00:22:23 -0000 On Wed, Apr 25, 2018 at 2:30 AM, Steve Wills wrote: > Hi, > > Recently on multiple systems running CURRENT, I've been seeing the > system become unresponsive. Leaving top(1) running has lead me to > notice that when this happens, the system is still responding to ping > and top over ssh is still working, but no new processes can start and > switching to other tasks doesn't work. In top, I do see pid 17, > [zfskern{txg_thread_enter}] monopolizing both CPU usage and disk IO. > Any ideas how to troubleshoot this? It doesn't appear to be a > hardware issue. Hi, Do you have something writing to a gzip compressed dataset? You can use the vfssnoop DTrace script from https://forums.freebsd.org/threads/sharing-of-dtrace-scripts.32855/#post-181816 to see who's writing what. I don't remember if it was exactly txg_thread_enter or whatever, but both CPU and disk sounds a lot like heavily compressed writes. In my case, the Epiphany browser was downloading a large malware database to ~/.config/epiphany/gsb-threats.db :D