Date: Fri, 23 Sep 2016 23:01:43 +0300 From: Slawa Olhovchenkov <slw@zxy.spb.ru> To: Julien Charbon <julien.charbon@gmail.com> Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-stable@FreeBSD.org, hiren panchasara <hiren@strugglingcoder.info> Subject: Re: 11.0 stuck on high network load Message-ID: <20160923200143.GG2840@zxy.spb.ru> In-Reply-To: <e4e0188c-b22b-29af-ed15-b650c3ec4553@gmail.com> References: <20160916181839.GC2960@zxy.spb.ru> <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> <f644cd52-4377-aa90-123a-3a2887972bbc@freebsd.org> <20160921195155.GW2840@zxy.spb.ru> <e4e0188c-b22b-29af-ed15-b650c3ec4553@gmail.com>
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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().help
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