Date: Fri, 16 Dec 2016 11:06:53 -0700 From: Ian Lepore <ian@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: How to use sem_timedwait? Message-ID: <1481911613.1972.74.camel@freebsd.org> In-Reply-To: <20161215171534.GV94325@kib.kiev.ua> References: <20161214074228.zh6q5zya2gszw4g6@hal9000.meka.no-ip.org> <1481748960.1889.398.camel@freebsd.org> <20161215002906.mllorgvvuovbdtze@hal9000.meka.no-ip.org> <1481775511.1889.450.camel@freebsd.org> <1481776532.1889.461.camel@freebsd.org> <20161215112050.GO94325@kib.kiev.ua> <1481817343.1889.467.camel@freebsd.org> <20161215171534.GV94325@kib.kiev.ua>
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On Thu, 2016-12-15 at 19:15 +0200, Konstantin Belousov wrote: > On Thu, Dec 15, 2016 at 08:55:43AM -0700, Ian Lepore wrote: > > > > It makes me feel a bit better to hear that it's only this machine, > > which is pretty old. I wonder if it has something to do with > > overclocking the cpu? I never have any other kind of timing > > trouble, > > though. (Given that I work in the field of precision timing, I'm a > > bit > > sensitive to such things.) > > > > revolution > sysctl kern.timecounter kern.eventtimer > > 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: TSC-low(1000) ACPI-fast(900) HPET(950) > > i8254(0) dummy(-1000000) > > kern.timecounter.hardware: TSC-low > > kern.timecounter.alloweddeviation: 0 > > kern.timecounter.stepwarnings: 0 > > kern.timecounter.tc.TSC-low.quality: 1000 > > kern.timecounter.tc.TSC-low.frequency: 2125044382 > > kern.timecounter.tc.TSC-low.counter: 1611837909 > > kern.timecounter.tc.TSC-low.mask: 4294967295 > > kern.timecounter.tc.ACPI-fast.quality: 900 > > kern.timecounter.tc.ACPI-fast.frequency: 3579545 > > kern.timecounter.tc.ACPI-fast.counter: 6548232 > > kern.timecounter.tc.ACPI-fast.mask: 16777215 > > kern.timecounter.tc.HPET.quality: 950 > > kern.timecounter.tc.HPET.frequency: 14318180 > > kern.timecounter.tc.HPET.counter: 3623382209 > > kern.timecounter.tc.HPET.mask: 4294967295 > > kern.timecounter.tc.i8254.quality: 0 > > kern.timecounter.tc.i8254.frequency: 1193182 > > kern.timecounter.tc.i8254.counter: 18218 > > kern.timecounter.tc.i8254.mask: 65535 > > kern.eventtimer.periodic: 0 > > kern.eventtimer.timer: LAPIC > > kern.eventtimer.idletick: 0 > > kern.eventtimer.singlemul: 2 > > kern.eventtimer.choice: LAPIC(600) HPET(350) HPET1(340) HPET2(340) > > HPET3(340) i8254(100) RTC(0) > > kern.eventtimer.et.HPET3.quality: 340 > > kern.eventtimer.et.HPET3.frequency: 14318180 > > kern.eventtimer.et.HPET3.flags: 3 > > kern.eventtimer.et.HPET2.quality: 340 > > kern.eventtimer.et.HPET2.frequency: 14318180 > > kern.eventtimer.et.HPET2.flags: 3 > > kern.eventtimer.et.HPET1.quality: 340 > > kern.eventtimer.et.HPET1.frequency: 14318180 > > kern.eventtimer.et.HPET1.flags: 3 > > kern.eventtimer.et.HPET.quality: 350 > > 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.i8254.quality: 100 > > kern.eventtimer.et.i8254.frequency: 1193182 > > kern.eventtimer.et.i8254.flags: 1 > > kern.eventtimer.et.LAPIC.quality: 600 > > kern.eventtimer.et.LAPIC.frequency: 85001804 > > kern.eventtimer.et.LAPIC.flags: 7 > > > > > > FreeBSD 10.3-STABLE #5 r308807: Fri Nov 18 09:51:39 MST 2016 > > ilepore@revolution.hippie.lan:/b/staging/machines/revolution10/ > > obj/b/staging/machines/revolution10/src/sys/REVOLUTION10 amd64 > > FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) > > 20140512 > > VT(vga): text 80x25 > > CPU: Intel(R) Xeon(R) CPU W3680 @ 3.33GHz (4250.09-MHz > > K8-class CPU) > > > > Origin="GenuineIntel" Id=0x206c2 Family=0x6 Model=0x2c Stepping > > =2 > > > > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTR > > R,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT, > > TM,PBE> > > > > Features2=0x29ee3ff<SSE3,PCLMULQDQ,DTES64,MON,DS_CPL,VMX,SMX,EST,TM > > 2,SSSE3,CX16,xTPR,PDCM,PCID,DCA,SSE4.1,SSE4.2,POPCNT,AESNI> > > AMD Features=0x2c100800<SYSCALL,NX,Page1GB,RDTSCP,LM> > > AMD Features2=0x1<LAHF> > > VT-x: PAT,HLT,MTF,PAUSE,EPT,UG,VPID > > TSC: P-state invariant, performance statistics > > real memory = 12884901888 (12288 MB) > > avail memory = 12425519104 (11849 MB) > > Event timer "LAPIC" quality 600 > > ACPI APIC Table: <092410 APIC1941> > > FreeBSD/SMP: Multiprocessor System Detected: 12 CPUs > > FreeBSD/SMP: 1 package(s) x 6 core(s) x 2 SMT threads > > > It is Westmere machine. If you switch to the HPET hardware for > eventtimer, > does it feel better ? > > Also please show output of sysctl dev.cpu.0. You are on stable/10, > there > were no usage of MWAIT instruction, but still switching to HPET might > make > a difference. > _ I tried LAPIC, HPET, and i8254 for eventtimer.hardware, there was no change with any of them. I tried turning periodic on, still no change. Changing alloweddeviation made no change. I tried different hardware choices for timecounter too (not that timecounting is showing any signs of trouble on this machine), no change. revolution > sysctl dev.cpu.0 dev.cpu.0.cx_usage: 100.00% 0.00% 0.00% last 303us dev.cpu.0.cx_lowest: C1 dev.cpu.0.cx_supported: C1/1/32 C2/2/96 C3/3/128 dev.cpu.0.freq_levels: 3334/143000 3333/130000 3200/117000 3067/105000 2933/94000 2800/85000 2667/76000 2533/68000 2400/61000 2267/54000 2133/48000 2000/43000 1867/39000 1733/35000 1600/32000 dev.cpu.0.freq: 3333 dev.cpu.0.temperature: 69.0C dev.cpu.0.coretemp.throttle_log: 0 dev.cpu.0.coretemp.tjmax: 101.0C dev.cpu.0.coretemp.resolution: 1 dev.cpu.0.coretemp.delta: 32 dev.cpu.0.%parent: acpi0 dev.cpu.0.%pnpinfo: _HID=none _UID=0 dev.cpu.0.%location: handle=\_PR_.P001 dev.cpu.0.%driver: cpu dev.cpu.0.%desc: ACPI CPU I also ran the test program on a couple servers at $work runing 10.3- stable, and they both showed identical behavior, with the result in the same range as on this machine: nsec = 9315538211 for 1000000 loops of 10000 nsec. One of those machines is running as a vmware guest: FreeBSD 10.3-STABLE-20161014 #2 r307350M: Mon Oct 17 18:07:23 MDT 2016 FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512 CPU: Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz (2197.45-MHz K8-class CPU) Origin="GenuineIntel" Id=0x206d2 Family=0x6 Model=0x2d Stepping=2 Features=0xfa3fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,DTS,MMX,FXSR,SSE,SSE2,SS> Features2=0x9fba2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,HV> AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM> AMD Features2=0x1<LAHF> Structured Extended Features=0x2<TSCADJ> TSC: P-state invariant Hypervisor: Origin = "VMwareVMware" real memory = 2147483648 (2048 MB) avail memory = 2050031616 (1955 MB) Event timer "LAPIC" quality 600 and the other is running on bare metal: FreeBSD 10.3-STABLE-20161014 #2 r307350M: Mon Oct 17 18:30:37 MDT 2016 CPU: Intel(R) Xeon(R) CPU X5550 @ 2.67GHz (2660.05-MHz K8-class CPU) Origin="GenuineIntel" Id=0x106a5 Family=0x6 Model=0x1a Stepping=5 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=0x9ce3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,SSE4.1,SSE4.2,POPCNT> AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM> AMD Features2=0x1<LAHF> VT-x: PAT,HLT,MTF,PAUSE,EPT,VPID TSC: P-state invariant, performance statistics real memory = 206158430208 (196608 MB) avail memory = 200380227584 (191097 MB) Event timer "LAPIC" quality 400 -- Ian
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