From owner-freebsd-current@freebsd.org Tue Apr 5 06:21:04 2016 Return-Path: Delivered-To: freebsd-current@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 D3652B01CB0 for ; Tue, 5 Apr 2016 06:21:04 +0000 (UTC) (envelope-from ohartman@zedat.fu-berlin.de) Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (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 951691AEA; Tue, 5 Apr 2016 06:21:04 +0000 (UTC) (envelope-from ohartman@zedat.fu-berlin.de) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.85) with esmtps (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (envelope-from ) id <1anKM8-002VII-2l>; Tue, 05 Apr 2016 08:20:52 +0200 Received: from p578a69f9.dip0.t-ipconnect.de ([87.138.105.249] helo=freyja.zeit4.iv.bundesimmobilien.de) by inpost2.zedat.fu-berlin.de (Exim 4.85) with esmtpsa (TLSv1.2:AES128-GCM-SHA256:128) (envelope-from ) id <1anKM7-001OFT-ND>; Tue, 05 Apr 2016 08:20:51 +0200 Date: Tue, 5 Apr 2016 08:20:47 +0200 From: "O. Hartmann" To: Cy Schubert Cc: Michael Butler , "K. Macy" , FreeBSD CURRENT Subject: Re: CURRENT slow and shaky network stability Message-ID: <20160405082047.670d7241@freyja.zeit4.iv.bundesimmobilien.de> In-Reply-To: <201604022314.u32NEvgs067448@slippy.cwsent.com> References: <20160402231955.41b05526.ohartman@zedat.fu-berlin.de> <201604022314.u32NEvgs067448@slippy.cwsent.com> Organization: FU Berlin X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.29; amd64-portbld-freebsd11.0) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Originating-IP: 87.138.105.249 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.21 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: Tue, 05 Apr 2016 06:21:04 -0000 On Sat, 02 Apr 2016 16:14:57 -0700 Cy Schubert wrote: > In message <20160402231955.41b05526.ohartman@zedat.fu-berlin.de>, "O. > Hartmann" > writes: > > --Sig_/eJJPtbrEuK1nN2zIpc7BmVr > > Content-Type: text/plain; charset=US-ASCII > > Content-Transfer-Encoding: quoted-printable > > > > Am Sat, 2 Apr 2016 11:39:10 +0200 > > "O. Hartmann" schrieb: > > > > > Am Sat, 2 Apr 2016 10:55:03 +0200 > > > "O. Hartmann" schrieb: > > >=20 > > > > Am Sat, 02 Apr 2016 01:07:55 -0700 > > > > Cy Schubert schrieb: > > > > =20 > > > > > In message <56F6C6B0.6010103@protected-networks.net>, Michael Butler > > > > > = > > writes: =20 > > > > > > -current is not great for interactive use at all. The strategy of > > > > > > pre-emptively dropping idle processes to swap is hurting .. big > > > > > > tim= > > e. =20 > > > > >=20 > > > > > FreeBSD doesn't "preemptively" or arbitrarily push pages out to > > > > > disk.= > > LRU=20 > > > > > doesn't do this. > > > > > =20 > > > > > >=20 > > > > > > Compare inactive memory to swap in this example .. > > > > > >=20 > > > > > > 110 processes: 1 running, 108 sleeping, 1 zombie > > > > > > CPU: 1.2% user, 0.0% nice, 4.3% system, 0.0% interrupt, 94.5% > > > > > > i= > > dle > > > > > > Mem: 474M Active, 1609M Inact, 764M Wired, 281M Buf, 119M Free > > > > > > Swap: 4096M Total, 917M Used, 3178M Free, 22% Inuse =20 > > > > >=20 > > > > > To analyze this you need to capture vmstat output. You'll see the > > > > > fre= > > e pool=20 > > > > > dip below a threshold and pages go out to disk in response. If you > > > > > ha= > > ve=20 > > > > > daemons with small working sets, pages that are not part of the > > > > > worki= > > ng=20 > > > > > sets for daemons or applications will eventually be paged out. This > > > > > i= > > s not=20 > > > > > a bad thing. In your example above, the 281 MB of UFS buffers are > > > > > mor= > > e=20 > > > > > active than the 917 MB paged out. If it's paged out and never used > > > > > ag= > > ain,=20 > > > > > then it doesn't hurt. However the 281 MB of buffers saves you I/O. > > > > > Th= > > e=20 > > > > > inactive pages are part of your free pool that were active at one > > > > > tim= > > e but=20 > > > > > now are not. They may be reclaimed and if they are, you've just > > > > > saved= > > more=20 > > > > > I/O. > > > > >=20 > > > > > Top is a poor tool to analyze memory use. Vmstat is the better tool > > > > > t= > > o help=20 > > > > > understand memory use. Inactive memory isn't a bad thing per se. > > > > > Moni= > > tor=20 > > > > > page outs, scan rate and page reclaims. > > > > >=20 > > > > > =20 > > > >=20 > > > > I give up! Tried to check via ssh/vmstat what is going on. Last lines > > > > b= > > efore broken > > > > pipe: > > > >=20 > > > > [...] > > > > procs memory page disks faults cpu > > > > r b w avm fre flt re pi po fr sr ad0 ad1 in sy cs > > > > = > > us sy id > > > > 22 0 22 5.8G 1.0G 46319 0 0 0 55721 1297 0 4 219 23907 > > > > 540= > > 0 95 5 0 > > > > 22 0 22 5.4G 1.3G 51733 0 0 0 72436 1162 0 0 108 40869 > > > > 345= > > 9 93 7 0 > > > > 15 0 22 12G 1.2G 54400 0 27 0 52188 1160 0 42 148 52192 > > > > 436= > > 6 91 9 0 > > > > 14 0 22 12G 1.0G 44954 0 37 0 37550 1179 0 39 141 86209 > > > > 436= > > 8 88 12 0 > > > > 26 0 22 12G 1.1G 60258 0 81 0 69459 1119 0 27 123 779569 > > > > 704= > > 359 87 13 0 > > > > 29 3 22 13G 774M 50576 0 68 0 32204 1304 0 2 102 507337 > > > > 484= > > 861 93 7 0 > > > > 27 0 22 13G 937M 47477 0 48 0 59458 1264 3 2 112 68131 > > > > 4440= > > 7 95 5 0 > > > > 36 0 22 13G 829M 83164 0 2 0 82575 1225 1 0 126 99366 > > > > 3806= > > 0 89 11 0 > > > > 35 0 22 6.2G 1.1G 98803 0 13 0 121375 1217 2 8 112 99371 > > > > 49= > > 99 85 15 0 > > > > 34 0 22 13G 723M 54436 0 20 0 36952 1276 0 17 153 29142 > > > > 443= > > 1 95 5 0 > > > > Fssh_packet_write_wait: Connection to 192.168.0.1 port 22: Broken pipe > > > >=20 > > > >=20 > > > > This makes this crap system completely unusable. The server (FreeBSD > > > > 11= > > .0-CURRENT #20 > > > > r297503: Sat Apr 2 09:02:41 CEST 2016 amd64) in question did > > > > poudriere= > > bulk job. I > > > > can not even determine what terminal goes down first - another one, > > > > muc= > > h more time > > > > idle than the one shwoing the "vmstat 5" output, is still alive!=20 > > > >=20 > > > > i consider this a serious bug and it is no benefit what happened since > > > > = > > this "fancy" > > > > update. :-( =20 > > >=20 > > > By the way - it might be of interest and some hint. > > >=20 > > > One of my boxes is acting as server and gateway. It utilises NAT, IPFW, > > > w= > > hen it is under > > > high load, as it was today, sometimes passing the network flow from ISP > > > i= > > nto the network > > > for clients is extremely slow. I do not consider this the reason for > > > coll= > > apsing ssh > > > sessions, since this incident happens also under no-load, but in the > > > over= > > all-view onto > > > the problem, this could be a hint - I hope.=20 > > > > I just checked on one box, that "broke pipe" very quickly after I started p= > > oudriere, > > while it did well a couple of hours before until the pipe broke. It seems i= > > t's load > > dependend when the ssh session gets wrecked, but more important, after the = > > long-haul > > poudriere run, I rebooted the box and tried again with the mentioned broken= > > pipe after a > > couple of minutes after poudriere ran. Then I left the box for several hour= > > s and logged > > in again and checked the swap. Although there was for hours no load or othe= > > r pressure, > > there were 31% of of swap used - still (box has 16 GB of RAM and is propell= > > ed by a XEON > > E3-1245 V2). > > > > 31%! Is it *actively* paging or is the 31% previously paged out and no > paging is *currently* being experienced? 31% of how swap space in total? > > Also, what does ps aumx or ps aumxww say? Pipe it to head -40 or similar. > > On FreeBSD 11.0-CURRENT #4 r297573: Tue Apr 5 07:01:19 CEST 2016 amd64, local network, no NAT. Stuck ssh session in the middle of administering and leaving the console/ssh session for a couple of minutes: root 2064 0.0 0.1 91416 8492 - Is 07:18 0:00.03 sshd: hartmann [priv] (sshd) hartmann 2108 0.0 0.1 91416 8664 - I 07:18 0:07.33 sshd: hartmann@pts/0 (sshd) root 72961 0.0 0.1 91416 8496 - Is 08:11 0:00.03 sshd: hartmann [priv] (sshd) hartmann 72970 0.0 0.1 91416 8564 - S 08:11 0:00.02 sshd: hartmann@pts/1 (sshd) The situation is worse and i consider this a serious bug.