Date: Mon, 26 Sep 2016 11:33:12 +0200 From: Julien Charbon <julien.charbon@gmail.com> To: Slawa Olhovchenkov <slw@zxy.spb.ru> 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: <dc2798ff-2ace-81f7-a563-18ffa1ace990@gmail.com> In-Reply-To: <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> <f644cd52-4377-aa90-123a-3a2887972bbc@freebsd.org> <20160921195155.GW2840@zxy.spb.ru> <e4e0188c-b22b-29af-ed15-b650c3ec4553@gmail.com> <20160923200143.GG2840@zxy.spb.ru> <20160925124626.GI2840@zxy.spb.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --12H9K1a6tfXsjU4KKUelKedFmxPMXjVBt Content-Type: multipart/mixed; boundary="oWtTp0oI5DUmUuqawNkH1QRl3r9fRm6UV"; protected-headers="v1" From: Julien Charbon <julien.charbon@gmail.com> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-stable@FreeBSD.org, hiren panchasara <hiren@strugglingcoder.info> Message-ID: <dc2798ff-2ace-81f7-a563-18ffa1ace990@gmail.com> Subject: Re: 11.0 stuck on high network load 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> <f644cd52-4377-aa90-123a-3a2887972bbc@freebsd.org> <20160921195155.GW2840@zxy.spb.ru> <e4e0188c-b22b-29af-ed15-b650c3ec4553@gmail.com> <20160923200143.GG2840@zxy.spb.ru> <20160925124626.GI2840@zxy.spb.ru> In-Reply-To: <20160925124626.GI2840@zxy.spb.ru> --oWtTp0oI5DUmUuqawNkH1QRl3r9fRm6UV Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Hi Slawa, On 9/25/16 2:46 PM, Slawa Olhovchenkov wrote: > On Fri, Sep 23, 2016 at 11:01:43PM +0300, Slawa Olhovchenkov wrote: >>> 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=3Dlockstat&manpath=3DFree= BSD+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 ev= ents/sec) >>>> >>>> --------------------------------------------------------------------= ----------- >>>> Count indv cuml rcnt nsec Lock Caller = =20 >>>> 140839 74% 74% 0.00 24659 tcpinp tcp_tw_2msl_sc= an+0xc6 =20 >>>> >>>> nsec ------ Time Distribution ------ count Stack = =20 >>>> 4096 | 913 tcp_twstart+0xa= 3 =20 >>>> 8192 |@@@@@@@@@@@@ 58191 tcp_do_segment+= 0x201f =20 >>>> 16384 |@@@@@@ 29594 tcp_input+0xe1c= =20 >>>> 32768 |@@@@ 23447 ip_input+0x15f = =20 >>>> 65536 |@@@ 16197 =20 >>>> 131072 |@ 8674 =20 >>>> 262144 | 3358 =20 >>>> 524288 | 456 =20 >>>> 1048576 | 9 =20 >>>> --------------------------------------------------------------------= ----------- >>>> Count indv cuml rcnt nsec Lock Caller = =20 >>>> 49180 26% 100% 0.00 15929 tcpinp tcp_tw_2msl_sca= n+0xc6 =20 >>>> >>>> nsec ------ Time Distribution ------ count Stack = =20 >>>> 4096 | 157 pfslowtimo+0x54= =20 >>>> 8192 |@@@@@@@@@@@@@@@ 24796 softclock_call_= cc+0x179=20 >>>> 16384 |@@@@@@ 11223 softclock+0x44 = =20 >>>> 32768 |@@@@ 7426 intr_event_exec= ute_handlers+0x95 >>>> 65536 |@@ 3918 =20 >>>> 131072 | 1363 =20 >>>> 262144 | 278 =20 >>>> 524288 | 19 =20 >>>> --------------------------------------------------------------------= ----------- >>> >>> This is interesting, it seems that you have two call paths competing= >>> for INP locks here: >>> >>> - pfslowtimo()/tcp_tw_2msl_scan(reuse=3D0) and >>> >>> - tcp_input()/tcp_twstart()/tcp_tw_2msl_scan(reuse=3D1) >> >> 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(). >=20 > Or may be locks leaks. > Or both. You are totally right, pfslowtimo()/tcp_tw_2msl_scan(reuse=3D0) is infinitely blocked on INP_WLOCK() by "something" (that could be related to write()). As I reached my limit of debugging without WITNESS, could you share your /etc/sysctl.conf, /boot/loader.conf files? And any specific configuration you have (like having a Nginx workers affinity, Nginx special options, etc.). Like that I can try to reproduce it on releng/11= =2E0. Thanks. -- Julien --oWtTp0oI5DUmUuqawNkH1QRl3r9fRm6UV-- --12H9K1a6tfXsjU4KKUelKedFmxPMXjVBt Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJX6OtnAAoJEKVlQ5Je6dhxlpsIAJ/qGR/MYHOe1EiiGqpVtL+s Wduh6AxK3/14NBvdjmxEU5RwfKc9tsP+wobaNJ6VZBSr7qqWXZgYM+E76iFiFgKE GuylXa4Rxb55F8W40pQko4YfYRkfrKc5GwthFtamDS3ASduASIUzDMY0Hh7EGoQD QyofDSTn8UEQmw8e4K3ryZ/qEExRh29lCSZBVtQMynoNSPQZf4lRhkM+paZoLiZW cfhw0xSuz9vzP4JbRW2UK0ZfLFzkjCBgUbcslRlc7Rf/969a39e3JxC5NTOnKejx PN7hPQYvLoaVZu6p5JmAuUD9k3y9RvOxxl0xLE/WPmAuhpi8ROKbW7Q+TGVoLrs= =xhuC -----END PGP SIGNATURE----- --12H9K1a6tfXsjU4KKUelKedFmxPMXjVBt--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?dc2798ff-2ace-81f7-a563-18ffa1ace990>