From owner-freebsd-stable@freebsd.org Sun Sep 25 12:46:36 2016 Return-Path: Delivered-To: freebsd-stable@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 07C74BE566A for ; Sun, 25 Sep 2016 12:46:36 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (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 BD07A405 for ; Sun, 25 Sep 2016 12:46:35 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from slw by zxy.spb.ru with local (Exim 4.86 (FreeBSD)) (envelope-from ) id 1bo8p8-000L2B-5k; Sun, 25 Sep 2016 15:46:26 +0300 Date: Sun, 25 Sep 2016 15:46:26 +0300 From: Slawa Olhovchenkov To: Julien Charbon Cc: Konstantin Belousov , freebsd-stable@FreeBSD.org, hiren panchasara Subject: Re: 11.0 stuck on high network load Message-ID: <20160925124626.GI2840@zxy.spb.ru> References: <20160916183053.GL9397@strugglingcoder.info> <20160916190330.GG2840@zxy.spb.ru> <78cbcdc9-f565-1046-c157-2ddd8fcccc62@freebsd.org> <20160919204328.GN2840@zxy.spb.ru> <8ba75d6e-4f01-895e-0aed-53c6c6692cb9@freebsd.org> <20160920202633.GQ2840@zxy.spb.ru> <20160921195155.GW2840@zxy.spb.ru> <20160923200143.GG2840@zxy.spb.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160923200143.GG2840@zxy.spb.ru> User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 25 Sep 2016 12:46:36 -0000 On Fri, Sep 23, 2016 at 11:01:43PM +0300, Slawa Olhovchenkov wrote: > On Wed, Sep 21, 2016 at 11:25:18PM +0200, Julien Charbon wrote: > > > > > Hi Slawa, > > > > On 9/21/16 9:51 PM, Slawa Olhovchenkov wrote: > > > On Wed, Sep 21, 2016 at 09:11:24AM +0200, Julien Charbon wrote: > > >> You can also use Dtrace and lockstat (especially with the lockstat -s > > >> option): > > >> > > >> https://wiki.freebsd.org/DTrace/One-Liners#Kernel_Locks > > >> https://www.freebsd.org/cgi/man.cgi?query=lockstat&manpath=FreeBSD+11.0-RELEASE > > >> > > >> But I am less familiar with Dtrace/lockstat tools. > > > > > > I am still use old kernel and got lockdown again. > > > Try using lockstat (I am save more output), interesting may be next: > > > > > > R/W writer spin on writer: 190019 events in 1.070 seconds (177571 events/sec) > > > > > > ------------------------------------------------------------------------------- > > > Count indv cuml rcnt nsec Lock Caller > > > 140839 74% 74% 0.00 24659 tcpinp tcp_tw_2msl_scan+0xc6 > > > > > > nsec ------ Time Distribution ------ count Stack > > > 4096 | 913 tcp_twstart+0xa3 > > > 8192 |@@@@@@@@@@@@ 58191 tcp_do_segment+0x201f > > > 16384 |@@@@@@ 29594 tcp_input+0xe1c > > > 32768 |@@@@ 23447 ip_input+0x15f > > > 65536 |@@@ 16197 > > > 131072 |@ 8674 > > > 262144 | 3358 > > > 524288 | 456 > > > 1048576 | 9 > > > ------------------------------------------------------------------------------- > > > Count indv cuml rcnt nsec Lock Caller > > > 49180 26% 100% 0.00 15929 tcpinp tcp_tw_2msl_scan+0xc6 > > > > > > nsec ------ Time Distribution ------ count Stack > > > 4096 | 157 pfslowtimo+0x54 > > > 8192 |@@@@@@@@@@@@@@@ 24796 softclock_call_cc+0x179 > > > 16384 |@@@@@@ 11223 softclock+0x44 > > > 32768 |@@@@ 7426 intr_event_execute_handlers+0x95 > > > 65536 |@@ 3918 > > > 131072 | 1363 > > > 262144 | 278 > > > 524288 | 19 > > > ------------------------------------------------------------------------------- > > > > This is interesting, it seems that you have two call paths competing > > for INP locks here: > > > > - pfslowtimo()/tcp_tw_2msl_scan(reuse=0) and > > > > - tcp_input()/tcp_twstart()/tcp_tw_2msl_scan(reuse=1) > > My current hypothesis: > > nginx do write() (or may be close()?) to socket, kernel lock > first inp in V_twq_2msl, happen callout for pfslowtimo() on the same > CPU core and tcp_tw_2msl_scan infinity locked on same inp. > > In this case you modification can't help, before next try we need some > like yeld(). Or may be locks leaks. Or both.