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Evilguru
Guru
Joined: 16 Aug 2005
Posts: 390
Location: England
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 Posted: Wed Jul 06, 2011 8:04 pm Post subject: Intel Sandy Bridge L3 Cache Disabled |
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Hello,
I have recently purchased a Core i7 (Sandy Bridge) based system. Upon running lshw I was alarmed to discover:
| Code: |
*-cpu
description: CPU
product: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz
vendor: Intel Corp.
physical id: 4
bus info: cpu@0
version: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz
serial: To Be Filled By O.E.M.
slot: LGA1155
size: 3431MHz
capacity: 3800MHz
width: 64 bits
clock: 100MHz
capabilities: x86-64 fpu fpu_exception wp 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 syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt aes xsave avx lahf_lm ida arat epb xsaveopt pln pts tpr_shadow vnmi flexpriority ept vpid
configuration: cores=4 enabledcores=1 threads=2
*-cache:0
description: L1 cache
physical id: 5
slot: L1-Cache
size: 256KiB
capacity: 256KiB
capabilities: internal write-back unified
*-cache:1
description: L2 cache
physical id: 6
slot: L2-Cache
size: 1MiB
capacity: 1MiB
capabilities: internal varies unified
*-cache:2 DISABLED
description: L3 cache
physical id: 7
slot: L3-Cache
size: 8MiB
capacity: 8MiB
capabilities: internal unified
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Is lshw talking nonsense or is the cache really disabled? (How can I find out?)
Regards, Freddie. |
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mattst88
Developer
Joined: 28 Oct 2004
Posts: 423
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| Posted: Wed Jul 06, 2011 11:08 pm Post subject: |
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I see it too on my 2500K with Asrock H67M motherboard:
| Code: | *-cache:0
description: L1 cache
physical id: 5
slot: L1-Cache
size: 128KiB
capacity: 128KiB
capabilities: internal write-through unified
*-cache:1
description: L2 cache
physical id: 6
slot: L2-Cache
size: 1MiB
capacity: 1MiB
capabilities: internal write-through unified
*-cache:2 DISABLED
description: L3 cache
physical id: 7
slot: L3-Cache
size: 6MiB
capacity: 6MiB
capabilities: internal write-back unified |
I'm going to do some research.
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whig
l33t
Joined: 27 Nov 2004
Posts: 973
Location: New Zealand
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| Posted: Wed Jul 06, 2011 11:55 pm Post subject: |
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| What does /proc/cpuinfo say about cache? |
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mattst88
Developer
Joined: 28 Oct 2004
Posts: 423
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| Posted: Thu Jul 07, 2011 12:22 am Post subject: |
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| Code: | | cache size : 6144 KB |
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<3
Veteran
Joined: 21 Oct 2004
Posts: 1085
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| Posted: Thu Jul 07, 2011 4:54 am Post subject: |
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| I am getting the same output on my sandy bridge laptop. On my Nehalem (Lynnfield) desktop it doesn't say that the L3 cache is disabled. |
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whig
l33t
Joined: 27 Nov 2004
Posts: 973
Location: New Zealand
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| Posted: Thu Jul 07, 2011 5:21 am Post subject: |
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I checked on my i3 2100T, seems fine here. It's running a vanilla kernel. Cache may be disabled in the bios but it would be strange to do so. Often a bios has reset to optimized defaults option.
| Code: | *-cache:0
description: L1 cache
physical id: 4
size: 128KiB
capacity: 128KiB
capabilities: internal varies
*-cache:1
description: L2 cache
physical id: 5
size: 512KiB
capacity: 512KiB
capabilities: internal varies unified
*-cache:2
description: L3 cache
physical id: 6
size: 3MiB
capacity: 3MiB
capabilities: internal varies unified |
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roarinelk
Guru
Joined: 04 Mar 2004
Posts: 520
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| Posted: Thu Jul 07, 2011 7:46 am Post subject: |
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| mattst88 wrote: | I see it too on my 2500K with Asrock H67M motherboard:
| Code: | *-cache:0
description: L1 cache
physical id: 5
slot: L1-Cache
size: 128KiB
capacity: 128KiB
capabilities: internal write-through unified
*-cache:1
description: L2 cache
physical id: 6
slot: L2-Cache
size: 1MiB
capacity: 1MiB
capabilities: internal write-through unified
*-cache:2 DISABLED
description: L3 cache
physical id: 7
slot: L3-Cache
size: 6MiB
capacity: 6MiB
capabilities: internal write-back unified |
I'm going to do some research. |
This looks like a dump of DMI data, which is IMO a very unreliable source
of system information. A better source of cache information is the
/sys/devices/system/cpu/* tree, it has a few cache/ subdirs. |
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