Date: Fri, 1 May 2009 16:10:40 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-current@FreeBSD.org Cc: pluknet <pluknet@gmail.com>, Jeff Roberson <jroberson@jroberson.net> Subject: Re: cannot compile sched_ule without options SMP Message-ID: <200905011610.42613.jkim@FreeBSD.org> In-Reply-To: <a31046fc0904302004r195750f2h586e08d9acf854d1@mail.gmail.com> References: <20090430013428.cb4f804b.nork@FreeBSD.org> <a31046fc0904301939la407bfek2f342b06c7d3ba29@mail.gmail.com> <a31046fc0904302004r195750f2h586e08d9acf854d1@mail.gmail.com>
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On Thursday 30 April 2009 11:04 pm, pluknet wrote:
> 2009/5/1 pluknet <pluknet@gmail.com>:
> > 2009/5/1 Jeff Roberson <jroberson@jroberson.net>:
> >> On Thu, 30 Apr 2009, pluknet wrote:
> >>> 2009/4/30 Jeff Roberson <jroberson@jroberson.net>:
> >>>> On SMP machines you should now see output like this:
> >>>> FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
> >>>> FreeBSD/SMP: 1 package(s) x 4 core(s) x 2 SMT threads
> >>>>
> >>>> If you detect any irregularities with kern.sched.topology_spec
> >>>> or this dmesg
> >>>> line please report them.
> >>>
> >>> Hi, Jeff.
> >>>
> >>> I have such mismatch. This is an Intel E7200.
> >>>
> >>> FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
> >>> FreeBSD/SMP: 1 package(s) x 1 core(s) x 2 HTT threads
> >>> cpu0 (BSP): APIC ID: 0
> >>> cpu1 (AP/HT): APIC ID: 1
> >>>
> >>> So it should be instead: 1 package(s) x 2 core(s)
> >>> cpu0 (BSP): APIC ID: 0
> >>> cpu1 (AP): APIC ID: 1
> >>
> >> Can you please repeat the following steps as I have done here:
> >
> > (kgdb) p/x cpu_high
> > $1 = 0x2
> > (kgdb) p/x cpu_cores
> > $2 = 0x1
> > (kgdb) p/x cpu_logical
> > $3 = 0x2
> > (kgdb) p/x cpu_feature
> > $4 = 0xbfebfbff
> > (kgdb) p/x logical_cpus
> > $5 = 0x2
> > (kgdb) p/x hyperthreading_cpus
> > $6 = 0x2
>
> Follow up myself:
>
> What is embarrassing me is HTT feature enabled. May the reason be
> in a buggy CPUID ?
No, the flag does not mean it supports Hyperthreading. It means more
than one logical core is supported (multi-threading) although the
name didn't change for historical reason. ;-)
Can you try the attached patch?
Thanks!
Jung-uk Kim
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--- sys/amd64/amd64/identcpu.c 29 Apr 2009 06:54:40 -0000 1.172
+++ sys/amd64/amd64/identcpu.c 1 May 2009 20:00:59 -0000
@@ -472,6 +472,24 @@
cpu_feature = regs[3];
cpu_feature2 = regs[2];
+ /*
+ * Clear "Limit CPUID Maxval" bit and get the highest
+ * basic CPUID function again if it is set from BIOS.
+ * It is necessary for probing correct CPU topology later.
+ * XXX This is only done on BSP.
+ */
+ if (cpu_vendor_id == CPU_VENDOR_INTEL &&
+ cpu_high > 0 && cpu_high < 4 &&
+ (cpu_feature & CPUID_HTT) != 0) {
+ uint64_t msr;
+ msr = rdmsr(MSR_IA32_MISC_ENABLE);
+ if ((msr & 0x400000ULL) != 0) {
+ wrmsr(MSR_IA32_MISC_ENABLE, msr & ~0x400000ULL);
+ do_cpuid(0, regs);
+ cpu_high = regs[0];
+ }
+ }
+
if (cpu_vendor_id == CPU_VENDOR_INTEL ||
cpu_vendor_id == CPU_VENDOR_AMD ||
cpu_vendor_id == CPU_VENDOR_CENTAUR) {
--- sys/i386/i386/identcpu.c 29 Apr 2009 06:54:40 -0000 1.201
+++ sys/i386/i386/identcpu.c 1 May 2009 20:00:59 -0000
@@ -323,15 +323,6 @@
strcat(cpu_model, "Pentium 4");
cpu = CPU_P4;
model = (cpu_id & 0x0f0) >> 4;
- if (model == 3 || model == 4 || model == 6) {
- uint64_t tmp;
-
- tmp = rdmsr(MSR_IA32_MISC_ENABLE);
- wrmsr(MSR_IA32_MISC_ENABLE,
- tmp & ~(1LL << 22));
- do_cpuid(0, regs);
- cpu_high = regs[0];
- }
break;
default:
strcat(cpu_model, "unknown");
@@ -1110,6 +1101,24 @@
cpu_vendor_id = find_cpu_vendor_id();
+ /*
+ * Clear "Limit CPUID Maxval" bit and get the highest
+ * basic CPUID function again if it is set from BIOS.
+ * It is necessary for probing correct CPU topology later.
+ * XXX This is only done on BSP.
+ */
+ if (cpu_vendor_id == CPU_VENDOR_INTEL &&
+ cpu_high > 0 && cpu_high < 4 &&
+ (cpu_feature & CPUID_HTT) != 0) {
+ uint64_t msr;
+ msr = rdmsr(MSR_IA32_MISC_ENABLE);
+ if ((msr & 0x400000ULL) != 0) {
+ wrmsr(MSR_IA32_MISC_ENABLE, msr & ~0x400000ULL);
+ do_cpuid(0, regs);
+ cpu_high = regs[0];
+ }
+ }
+
/* Detect AMD features (PTE no-execute bit, 3dnow, 64 bit mode etc) */
if (cpu_vendor_id == CPU_VENDOR_INTEL ||
cpu_vendor_id == CPU_VENDOR_AMD) {
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