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curmudgeon
Veteran
Joined: 08 Aug 2003
Posts: 1744
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 Posted: Tue Sep 18, 2007 5:52 am Post subject: No SMP :( |
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Pentium 4 with hyperthreading:
| Code: | # dog /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Pentium(R) 4 CPU 2.60GHz
stepping : 9
cpu MHz : 2600.000
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : 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 ht tm pbe up cid xtpr
bogomips : 5204.50
clflush size : 64 |
But (as seen above), the kernel only sees one processor.
The relevant part of /usr/src/linux-2.6.22-gentoo-r2/.config:
| Code: | #
# Processor type and features
#
# CONFIG_TICK_ONESHOT is not set
# CONFIG_NO_HZ is not set
# CONFIG_HIGH_RES_TIMERS is not set
CONFIG_SMP=y
CONFIG_X86_PC=y
# CONFIG_X86_ELAN is not set
# CONFIG_X86_VOYAGER is not set
# CONFIG_X86_NUMAQ is not set
# CONFIG_X86_SUMMIT is not set
# CONFIG_X86_BIGSMP is not set
# CONFIG_X86_VISWS is not set
# CONFIG_X86_GENERICARCH is not set
# CONFIG_X86_ES7000 is not set
# CONFIG_PARAVIRT is not set
# CONFIG_M386 is not set
# CONFIG_M486 is not set
# CONFIG_M586 is not set
# CONFIG_M586TSC is not set
# CONFIG_M586MMX is not set
# CONFIG_M686 is not set
# CONFIG_MPENTIUMII is not set
# CONFIG_MPENTIUMIII is not set
# CONFIG_MPENTIUMM is not set
# CONFIG_MCORE2 is not set
CONFIG_MPENTIUM4=y
# CONFIG_MK6 is not set
# CONFIG_MK7 is not set
# CONFIG_MK8 is not set
# CONFIG_MCRUSOE is not set
# CONFIG_MEFFICEON is not set
# CONFIG_MWINCHIPC6 is not set
# CONFIG_MWINCHIP2 is not set
# CONFIG_MWINCHIP3D is not set
# CONFIG_MGEODEGX1 is not set
# CONFIG_MGEODE_LX is not set
# CONFIG_MCYRIXIII is not set
# CONFIG_MVIAC3_2 is not set
# CONFIG_MVIAC7 is not set
# CONFIG_X86_GENERIC is not set
CONFIG_X86_CMPXCHG=y
CONFIG_X86_L1_CACHE_SHIFT=7
CONFIG_X86_XADD=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
# CONFIG_ARCH_HAS_ILOG2_U32 is not set
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
CONFIG_X86_TSC=y
CONFIG_X86_CMOV=y
CONFIG_X86_MINIMUM_CPU_MODEL=4
# CONFIG_HPET_TIMER is not set
CONFIG_NR_CPUS=2
CONFIG_SCHED_SMT=y
# CONFIG_SCHED_MC is not set
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_BKL=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_MCE=y
# CONFIG_X86_MCE_NONFATAL is not set
# CONFIG_X86_MCE_P4THERMAL is not set
CONFIG_VM86=y
# CONFIG_TOSHIBA is not set
# CONFIG_I8K is not set
# CONFIG_X86_REBOOTFIXUPS is not set
# CONFIG_MICROCODE is not set
CONFIG_X86_MSR=y
# CONFIG_X86_CPUID is not set |
What did I do wrong? |
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dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3468
Location: Canada
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| Posted: Tue Sep 18, 2007 5:58 am Post subject: |
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| And why do you think Pentium4 has multiple cores ? |
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curmudgeon
Veteran
Joined: 08 Aug 2003
Posts: 1744
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| Posted: Tue Sep 18, 2007 7:21 am Post subject: |
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| dmpogo wrote: | | And why do you think Pentium4 has multiple cores ? |
It doesn't, but it has hyperthreading (note the "ht" in the flags), which lets it act like two processors. The kernels in all of my other Pentium 4s (single processor machines) see two processors, like this:
| Code: | dog /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 3
model name : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping : 4
cpu MHz : 3000.000
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : 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 ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr
bogomips : 6005.73
clflush size : 64
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 3
model name : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping : 4
cpu MHz : 3000.000
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : 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 ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr
bogomips : 6001.47
clflush size : 64 |
RTFM: http://gentoo.org/doc/en/kernel-config.xml
| Quote: | | Many of Intel's CPUs support a technology which they call hyper-threading, which is where the CPU is actually viewed by the system as two logical processors. |
I do have the kernel configuration options set according to that guide. |
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SeeksTheMoon
Apprentice
Joined: 24 Sep 2003
Posts: 163
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| Posted: Tue Sep 18, 2007 8:30 am Post subject: |
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emerge microcode-ctl and enable the microcode option in your kernel. Maybe it's a bug. I need to use microcode because my mobile CPU can use more speedstep values afterwards.
Oh, btw: I guess HT is not disabled in your BIOS? |
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curmudgeon
Veteran
Joined: 08 Aug 2003
Posts: 1744
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| Posted: Tue Sep 18, 2007 12:38 pm Post subject: |
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| SeeksTheMoon wrote: | | emerge microcode-ctl and enable the microcode option in your kernel. Maybe it's a bug. I need to use microcode because my mobile CPU can use more speedstep values afterwards. |
I will have to look at that a little later. I can't recompile and reboot that machine right now
| SeeksTheMoon wrote: | | Oh, btw: I guess HT is not disabled in your BIOS? |
I did look in the BIOS, and saw nothing about it. |
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pa1983
Tux's lil' helper
Joined: 09 Jan 2004
Posts: 101
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| Posted: Tue Sep 18, 2007 4:18 pm Post subject: |
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HT may boost performance whit about 5% tops on heavy loaded servers and things like that. On a desktop its close to 0% in most cases. Its also in theory a security risk, at least on Pentium 4. I cant really see any big point in having on on any way.
Just my 5 cents.
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NAS: i3 4360 3.7Ghz, 20Gb ram, 256Gb SSD, 65Tb HDD, NIC: Intel 2x1Gbit, Realtek 2.5Gbit
ROUTER: J1900 2Ghz, 8Gb ram, 128Gb SSD, NIC: 2x1Gbit, WIFI: Atheros AR9462 and AR5005G |
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eccerr0r
Watchman
Joined: 01 Jul 2004
Posts: 9891
Location: almost Mile High in the USA
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| Posted: Tue Sep 18, 2007 5:57 pm Post subject: |
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https://forums.gentoo.org/viewtopic-t-580679-highlight-.html
https://forums.gentoo.org/viewtopic-t-578089-highlight-.html
Not all P4s have it enabled despite all P4s having the CPUFLAG for HT.
BTW, I think that "security hole risk" is pretty much the same for any multithreaded CPU with shared memories, people have been claiming it to manifest on multicore and SMP systems in general.
It depends on the applications you're running whether you'll see an overall throughput speedup through SMT. For single threaded apps you'll likely see a very slight slowdown, but if you choose your threads properly you'll most definitely see an improvement.
_________________
Intel Core i7 2700K/Radeon R7 250/24GB DDR3/256GB SSD
What am I supposed watching? |
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curmudgeon
Veteran
Joined: 08 Aug 2003
Posts: 1744
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| Posted: Tue Sep 18, 2007 9:41 pm Post subject: |
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| Thank you for the explanation eccerr0r. |
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zeek
Guru
Joined: 16 Nov 2002
Posts: 480
Location: Bantayan Island
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| Posted: Mon Sep 24, 2007 4:02 am Post subject: |
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Do you have ACPI enabled in power management? Without that in newer kernels they wont see the extra ...uh hypercore.
I usually enable processor and thermal zone while I'm at it. |
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