Date: Fri, 05 Mar 2021 16:03:11 +0900 (JST) From: Yasuhiro Kimura <yasu@utahime.org> To: freebsd-current@freebsd.org Subject: Re: Waiting for bufdaemon Message-ID: <20210305.160311.867123118349124334.yasu@utahime.org> In-Reply-To: <20210128.050242.1986722766748729591.yasu@utahime.org> References: <20210115.201030.1395690536446474720.yasu@utahime.org> <20210116.040323.136067379540977557.yasu@utahime.org> <20210128.050242.1986722766748729591.yasu@utahime.org>
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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 CPU) >> Origin="GenuineIntel" Id=0x906ed Family=0x6 Model=0x9e Stepping=13 >> Features=0x1783fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE,SSE2,HTT> >> Features2=0x5eda2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AESNI,XSAVE,OSXSAVE,AVX,RDRAND> >> AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM> >> AMD Features2=0x121<LAHF,ABM,Prefetch> >> Structured Extended Features=0x842421<FSGSBASE,AVX2,INVPCID,NFPUSG,RDSEED,CLFLUSHOPT> >> Structured Extended Features3=0x30000400<MD_CLEAR,L1DFL,ARCH_CAP> >> IA32_ARCH_CAPS=0x29<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 time when we > have to effectively disable TSC use in VM. For instance, it was reported > (complained) in https://github.com/JuliaLang/julia/issues/38877 that > 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. Best Regards. --- Yasuhiro Kimura
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