Date: Fri, 09 Jul 2004 13:33:32 -0500 From: Jon Noack <noackjr@alumni.rice.edu> To: Kenneth Culver <culverk@sweetdreamsracing.biz> Cc: Steve Kargl <sgk@troutmask.apl.washington.edu> Subject: Re: Native preemption is the culprit [was Re: today's CURRENT lockups] Message-ID: <40EEE4FC.7070001@alumni.rice.edu> In-Reply-To: <20040709143125.b48g4s4cogskg88s@www.sweetdreamsracing.biz> References: <20040705184940.GA2651@tybalt.greiner.local> <200407081317.53981.jhb@FreeBSD.org> <20040709111955.2901ce5b.taku@tackymt.homeip.net> <200407091315.16899.jhb@FreeBSD.org> <40EED38D.9010903@alumni.rice.edu> <20040709172511.GA10540@troutmask.apl.washington.edu> <40EEDBB1.6090903@alumni.rice.edu> <20040709180635.GA11419@troutmask.apl.washington.edu> <40EEE01C.6090400@alumni.rice.edu> <20040709143125.b48g4s4cogskg88s@www.sweetdreamsracing.biz>
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On 07/09/04 13:31, Kenneth Culver wrote: > Quoting Jon Noack <noackjr@alumni.rice.edu>: >> On 07/09/04 13:06, Steve Kargl wrote: >>> On Fri, Jul 09, 2004 at 12:53:53PM -0500, Jon Noack wrote: >>>> On 07/09/04 12:25, Steve Kargl wrote: >>>>> On Fri, Jul 09, 2004 at 12:19:09PM -0500, Jon Noack wrote: >>>>>> On 07/09/04 12:15, John Baldwin wrote: >>>>>>> My test machine is not a true SMP machine either, just >>>>>>> HTT. It has been running a -j 256 worldloop overnight >>>>>>> with no problems, so I committed a slightly modified >>>>>>> version of the patch yesterday. >>>>>> >>>>>> Did you test with a UP kernel? After your latest commit I >>>>>> have been experiencing regular hard locks on my pre-HTT P4 >>>>>> machine. Backing out rev. 1.114 of sched_ule.c fixes it. >>>>>> See my previous message (Re: FreeBSD keeps hanging......): >>>>>> http://docs.freebsd.org/cgi/mid.cgi?40EECC49.3070501 >>>>> >>>>> I've tested it on a UP kernel (HTT enabled, ACPI disabled, >>>>> APIC enabled, ULE). Appears to work fine. >>>> >>>> Perhaps it's just extraneous information, but if it's really a >>>> UP kernel (as in, no 'options SMP') then whether you have HTT >>>> enabled doesn't matter at all -- the kernel won't use it. >>> >>> Yes, I know. :-) I'm just reporting what dmesg tells me about >>> the CPU. >>> >>> CPU: Mobile Intel(R) Pentium(R) 4 - M CPU 2.00GHz (1994.12-MHz >>> 686-class CPU) Origin = "GenuineIntel" Id = 0xf27 Stepping = 7 >>> >>> Features=0xbfebf9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> >> >> Mine also lists HTT, but doesn't actually support it: CPU: Intel(R) >> Pentium(R) 4 CPU 2.53GHz (2539.10-MHz 686-class CPU) Origin = >> "GenuineIntel" Id = 0xf24 Stepping = 4 >> >> Features=0x3febfbff<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> >> >> I remember a discussion about this a long time ago, but don't >> remember the details. Regardless, the flag doesn't actually mean >> the processor supports HTT. > > I was under the impression that all P4's support HTT, but a lot of > bioses don't allow users to enable it. Nope, they didn't support HTT until the 3.06 GHz (533 MHz bus). Models introduced after that support HTT; if they use an 800 MHz bus then they do support HTT, regardless of speed. That's why you can get a 2.4 GHz (800 MHz bus) w/ HTT but an older 2.8 GHz (533 MHz bus) won't support it. In any case, the flag just means we can check if the processor supports HTT: http://lists.freebsd.org/pipermail/freebsd-current/2004-January/017920.html Jon
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