Date: Fri, 9 Jul 2004 15:31:14 -0400 From: John Baldwin <jhb@FreeBSD.org> To: noackjr@alumni.rice.edu Cc: Steve Kargl <sgk@troutmask.apl.washington.edu> Subject: Re: Native preemption is the culprit [was Re: today's CURRENT lockups] Message-ID: <200407091531.14689.jhb@FreeBSD.org> In-Reply-To: <40EEE01C.6090400@alumni.rice.edu> References: <20040705184940.GA2651@tybalt.greiner.local> <20040709180635.GA11419@troutmask.apl.washington.edu> <40EEE01C.6090400@alumni.rice.edu>
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On Friday 09 July 2004 02:12 pm, Jon Noack wrote: > 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,C > >MOV,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,MC >A,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. The flag means you can ask the CPU how many cores it has, but it may reply with "I have 1 core." If there is more than 1 core, then we print out a second line saying how many cores there are on each CPU. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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