Re: TSC as timecounter makes system lag

On Sun, Jan 15, 2017 at 10:35:26PM +0800, Jia-Shiun Li wrote:
> Sorry just saw this. Bad Gmail.
> 
> 
> On Fri, Jan 13, 2017 at 8:05 PM, Konstantin Belousov <kostikbel_at_gmail.com>
> wrote:
> 
> > On Fri, Jan 13, 2017 at 08:26:04AM +0800, Jia-Shiun Li wrote:
> > > Hi all,
> > >
> > > since 2 or 3 weeks ago, I noticed that my old Penryn-based Intel Pentium
> > > T4200 notebook lagged a lot. System time was running a lot slower,
> > > sometimes even looked like it freezed. Keystroke repeat rate was slow
> > too.
> > >
> > > Since system time is slow, I tried to change timecounter from default TSC
> > > to HPET. And it resumed normal immediately.
> > Please show the output of sysctl kern.timecounter and kern.eventtimer.
> > I suspect that you changed eventtimer and not timecounter.
> >
> 
> Files attached. I changed it by "sysctl kern.timecounter.hardware=HPET"
> 
> 
> > The same world binary works fine on other Ivybridge and Haswell desktops,
> > > so I assume this may be related to CPU or mainboard generations.
> > >
> > > version is
> > >
> > > FreeBSD jsli-nb 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r311687: Mon Jan  9
> > > 04:07:27 CST 2017
> > > jsli_at_4cbsd:/personal/freebsd/obj/x64/personal/freebsd/
> > fbsdsrc/sys/MINIMAL-NODEBUG
> > > amd64
> > >
> > > and CPU is
> > >
> > > CPU: Pentium(R) Dual-Core CPU       T4200  _at_ 2.00GHz (1995.04-MHz
> > K8-class
> > > CPU)
> > >   Origin="GenuineIntel"  Id=0x1067a  Family=0x6  Model=0x17  Stepping=10
> > >
> > > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,
> > APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,
> > MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> > >
> > > Features2=0xc00e39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,
> > SSSE3,CX16,xTPR,PDCM,XSAVE,OSXSAVE>
> > >   AMD Features=0x20100800<SYSCALL,NX,LM>
> > >   AMD Features2=0x1<LAHF>
> > >   TSC: P-state invariant, performance statistics
> > >
> > > Tested similar OS rev on another Intel Core 2 Duo E7400 Wolfdale (the
> > same
> > > generation as the Pentium T4200). The same lag also happens on it.
> > >
> > > BTW on both system, cpuX:timer interrupts do not fire at all and count
> > > remains 0.
> > It is known that LAPIC is shut down in C2 and deeper CPU sleep states on
> > Core2.  FreeBSD 11 (and HEAD) started using MWAIT and requesting deep
> > wait states from BIOS.  If the configuration uses LAPIC and deep sleeps
> > are enabled, eventtimers do not work reliably.
> >
> 
> > Default configuration should strongly prefer HPET eventtimer over LAPIC for
> > machines which do not have LAPIC armed in Cx states, see r309189.  If you
> > do not have any customizations of eventtimer selection, then please provide
> > verbose dmesg from your boot.
> >
> > If you prefer to not use deep Cx and MWAIT, set loader tunable
> > debug.acpi.disabled to include word "mwait", see acpi(4).  You can check
> > that this worked by looking at sysctl dev.cpu.N output.
> >
> 
> Thanks for the explanation. Looks eventtimer favored HPET over LAPIC
> like you described on this notebook.
I still do not understand.  Is the sysctl output below from the pristine
boot where no timecounter/eventtimer reconfiguration were done ?

Show me exact command which you used to revive the machine.  Do not describe
it by words, copy/paste from the console.

> 
> -Jia-Shiun.

> kern.eventtimer.periodic: 0
> kern.eventtimer.timer: HPET
> kern.eventtimer.idletick: 0
> kern.eventtimer.singlemul: 2
> kern.eventtimer.choice: HPET(450) HPET1(440) HPET2(440) HPET3(440) LAPIC(100) i8254(100) RTC(0)
> kern.eventtimer.et.i8254.quality: 100
> kern.eventtimer.et.i8254.frequency: 1193182
> kern.eventtimer.et.i8254.flags: 1
> kern.eventtimer.et.HPET3.quality: 440
> kern.eventtimer.et.HPET3.frequency: 14318180
> kern.eventtimer.et.HPET3.flags: 3
> kern.eventtimer.et.HPET2.quality: 440
> kern.eventtimer.et.HPET2.frequency: 14318180
> kern.eventtimer.et.HPET2.flags: 3
> kern.eventtimer.et.HPET1.quality: 440
> kern.eventtimer.et.HPET1.frequency: 14318180
> kern.eventtimer.et.HPET1.flags: 3
> kern.eventtimer.et.HPET.quality: 450
> kern.eventtimer.et.HPET.frequency: 14318180
> kern.eventtimer.et.HPET.flags: 3
> kern.eventtimer.et.RTC.quality: 0
> kern.eventtimer.et.RTC.frequency: 32768
> kern.eventtimer.et.RTC.flags: 17
> kern.eventtimer.et.LAPIC.quality: 100
> kern.eventtimer.et.LAPIC.frequency: 0
> kern.eventtimer.et.LAPIC.flags: 15
> kern.timecounter.tsc_shift: 1
> kern.timecounter.smp_tsc_adjust: 0
> kern.timecounter.smp_tsc: 1
> kern.timecounter.invariant_tsc: 1
> kern.timecounter.fast_gettime: 1
> kern.timecounter.tick: 1
> kern.timecounter.choice: ACPI-fast(900) i8254(0) HPET(950) TSC(1000) dummy(-1000000)
> kern.timecounter.hardware: TSC
> kern.timecounter.alloweddeviation: 5
> kern.timecounter.stepwarnings: 0
> kern.timecounter.tc.ACPI-fast.quality: 900
> kern.timecounter.tc.ACPI-fast.frequency: 3579545
> kern.timecounter.tc.ACPI-fast.counter: 79078
> kern.timecounter.tc.ACPI-fast.mask: 16777215
> kern.timecounter.tc.i8254.quality: 0
> kern.timecounter.tc.i8254.frequency: 1193182
> kern.timecounter.tc.i8254.counter: 55592
> kern.timecounter.tc.i8254.mask: 65535
> kern.timecounter.tc.HPET.quality: 950
> kern.timecounter.tc.HPET.frequency: 14318180
> kern.timecounter.tc.HPET.counter: 1931486323
> kern.timecounter.tc.HPET.mask: 4294967295
> kern.timecounter.tc.TSC.quality: 1000
> kern.timecounter.tc.TSC.frequency: 1995044550
> kern.timecounter.tc.TSC.counter: 2329785074
> kern.timecounter.tc.TSC.mask: 4294967295

> Copyright (c) 1992-2017 The FreeBSD Project.
> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
> 	The Regents of the University of California. All rights reserved.
> FreeBSD is a registered trademark of The FreeBSD Foundation.
> FreeBSD 12.0-CURRENT #0 r311687: Mon Jan  9 04:07:27 CST 2017
>     jsli_at_4cbsd:/personal/freebsd/obj/x64/personal/freebsd/fbsdsrc/sys/MINIMAL-NODEBUG amd64
> FreeBSD clang version 3.9.1 (tags/RELEASE_391/final 289601) (based on LLVM 3.9.1)
> VT(vga): resolution 640x480
> CPU: Pentium(R) Dual-Core CPU       T4200  _at_ 2.00GHz (1995.04-MHz K8-class CPU)
>   Origin="GenuineIntel"  Id=0x1067a  Family=0x6  Model=0x17  Stepping=10
>   Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>   Features2=0xc00e39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM,XSAVE,OSXSAVE>
>   AMD Features=0x20100800<SYSCALL,NX,LM>
>   AMD Features2=0x1<LAHF>
>   TSC: P-state invariant, performance statistics
> real memory  = 4294967296 (4096 MB)
> avail memory = 4088070144 (3898 MB)
> Event timer "LAPIC" quality 100
> ACPI APIC Table: <ACRSYS ACRPRDCT>
> FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
> FreeBSD/SMP: 1 package(s) x 2 core(s)
> random: unblocking device.
> ioapic0: Changing APIC ID to 4
> ioapic0 <Version 2.0> irqs 0-23 on motherboard
> SMP: AP CPU #1 Launched!
This is not a verbose dmesg.