Date: Sat, 06 Mar 2021 11:46:58 +0100 From: Alexander Leidinger <Alexander@leidinger.net> To: freebsd-current@freebsd.org Subject: Re: Waiting for bufdaemon Message-ID: <20210306114658.Horde.3TT5LEaEorYtcBz_kyAYJPI@webmail.leidinger.net> In-Reply-To: <YEKYDlPuvn6TL4xs@kib.kiev.ua> References: <20210115.201030.1395690536446474720.yasu@utahime.org> <20210116.040323.136067379540977557.yasu@utahime.org> <20210128.050242.1986722766748729591.yasu@utahime.org> <20210305.160311.867123118349124334.yasu@utahime.org> <YEKYDlPuvn6TL4xs@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
This message is in MIME format and has been PGP signed. --=_TFwLucKTOLGmAR3L0ewLpoc Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Quoting Konstantin Belousov <kostikbel@gmail.com> (from Fri, 5 Mar=20=20 2021=2022:43:58 +0200): > On Fri, Mar 05, 2021 at 04:03:11PM +0900, Yasuhiro Kimura wrote: >> Dear src committers, >> >> From: Yasuhiro Kimura <yasu@utahime.org> >> Subject: Re: Waiting for bufdaemon >> Date: Thu, 28 Jan 2021 05:02:42 +0900 (JST) >> >> >>> I have been experiencing same problem with my 13-CURRENT amd64 >> >>> VirtualBox VM for about a month. The conditions that the problem >> >>> happens are unclear and all what I can say is >> >>> >> >>> * It happens only after I login in the VM and do something for a >> >>> while. If I boot the VM and shut it down immediately, it never >> >>> happens. >> >>> * When the problem happens, one or more unkillable processes seem to >> >>> be left. >> >> >> >> CPU of my host is not AMD but Intel. According to the >> >> /var/run/dmesg.boot of VM, information of CPU is as following. >> >> >> >> CPU: Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz (3000.09-MHz K8-class CP= U) >> >> Origin=3D"GenuineIntel" Id=3D0x906ed Family=3D0x6 Model=3D0x9e = Stepping=3D13 >> >>=20=20=20=20 >>=20Features=3D0x1783fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR= ,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE,SSE2,HTT> >> >>=20=20=20=20 >>=20Features2=3D0x5eda2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MO= VBE,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,RDRAND> >> >> AMD Features=3D0x28100800<SYSCALL,NX,RDTSCP,LM> >> >> AMD Features2=3D0x121<LAHF,ABM,Prefetch> >> >> Structured Extended=20=20 >>=20Features=3D0x842421<FSGSBASE,AVX2,INVPCID,NFPUSG,RDSEED,CLFLUSHOPT> >> >> Structured Extended Features3=3D0x30000400<MD_CLEAR,L1DFL,ARCH_CAP> >> >> IA32_ARCH_CAPS=3D0x29<RDCL_NO,SKIP_L1DFL_VME,MDS_NO> >> >> TSC: P-state invariant >> >> >> >> Just FYI. >> > >> > It took for a while to investigate, but according to the result of >> > bisect following commit is the source of problem in my case. >> > >> > ---------------------------------------------------------------------- >> > commit 84eaf2ccc6a >> > Author: Konstantin Belousov <kib@FreeBSD.org> >> > Date: Mon Dec 21 19:02:31 2020 +0200 >> > >> > x86: stop punishing VMs with low priority for TSC timecounter >> > >> > I suspect that virtualization techniques improved from the=20=20 >>=20time when we >> > have to effectively disable TSC use in VM. For instance, it=20=20 >>=20was reported >> > (complained) in https://github.com/JuliaLang/julia/issues/38877 th= at >> > FreeBSD is groundlessly slow on AWS with some loads. >> > >> > Remove the check and start watching for complaints. >> > >> > Reviewed by: emaste, grehan >> > Discussed with: cperciva >> > Sponsored by: The FreeBSD Foundation >> > Differential Revision: https://reviews.freebsd.org/D27629 >> > ---------------------------------------------------------------------- >> > >> > I confirmed the problem still happens with 5c325977b11 but reverting >> > above commit fixes it. >> >> Would someone please revert above commit from main, stable/13 and >> releng/13.0? As I wrote previous mail I submitted this problem to >> Bugzilla as bug 253087 and added the committer to Cc. But there is no >> response for 34 days. >> >> I confirmed the problem still happens with 37cd6c20dbc of main and >> 13.0-RC1. > > My belief is that this commit helps more users than it hurts. Namely, > the VMWare and KVM users, which are majority, use fast timecounter, > comparing to the more niche hypervisors like VirtualBox. > > For you, a simple but manual workaround, setting the timecounter to > ACPI (?) or might be HPET, with a loader tunable, should do it. Do you propose this to him as a test if this solves the issue with the=20= =20 intend=20to change the code to use a more suitable TC if VirtualBox is=20= =20 detected? Bye, Alexander. --=20 http://www.Leidinger.net Alexander@Leidinger.net: PGP 0x8F31830F9F2772BF http://www.FreeBSD.org netchild@FreeBSD.org : PGP 0x8F31830F9F2772BF --=_TFwLucKTOLGmAR3L0ewLpoc Content-Type: application/pgp-signature Content-Description: Digitale PGP-Signatur Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJgQ12iAAoJEBINsJsD+NiG1gsP/jY4NII2uSQjR0fwFY5WtQA9 r0F2DeVJtX+J7m/3xudvHUWIIOr0qlqniXpvIROIf5VZ5heoBtb8yv8O4YBnk6sQ QDUxkra+A1K93O44UYTmkfUeCjXF4ouWs+kUXXc5UMyfisjJQn/BnJnZU/qymWtO 0JQXrLGeSttMV5qdIOLs+coiaaJyqJJ0jqpAH6k2fnUfNYvoGy33UOW649UhnUTV oExPtnNAtz3j02816O0jL5ReuaFSci8aaHHFhaLeWZy88bweF54XSpspoqUr9Czm hcD9Dx1lewYm/g2/2GVNGTmsq3RfkmOBoQr3yvS+AVK4kTCoMv/Zn06OGGlDma+f /d183dFTvQ8+uJGBh0WQBUOYIxdT0BmEq9xLNLmnuB93Q4Fk/s3qaOaavPyKAIh5 LexojEskZl/MFu79ToWeZTchjAXT8FpzP9i/oxnq/zriBg3EM2W6/vdO2DHRk6Ts HcSOAEXUgzb0bFDsfbm9pTg9z2GZmV1wNFBonajsO1NRX8tl3kT51S6wG2PWH9FT /JqEKGA80+NlAQsu9A3jsyOfj3a9zAVQnv2QO0J+YXrPTRhSVUJTMXUd7/AghOkE LIbpPYAVA1o0ZQxs1DwLTY4AmNRuiXyr6b/GdFNNNHnMNljH2Z1iFEZKBSCLxnH5 rmpmibOhm9031buV47R1 =hIWL -----END PGP SIGNATURE----- --=_TFwLucKTOLGmAR3L0ewLpoc--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20210306114658.Horde.3TT5LEaEorYtcBz_kyAYJPI>