Software Tuning, Performance Optimization & Platform Monitoring
Discussion regarding monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform updating.

Shared L1 data cache

Divino_C_
New Contributor I
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Hello,

does Ivy Bridge (i7 3630qm) share L1 data cache between logical processors? How is it done?

thanks,
César. 

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SergeyKostrov
Valued Contributor II
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>>...does Ivy Bridge (i7 3630qm) share L1 data cache between logical processors?.. I don't think so and please take at ark.intel.com for technical details. When your CPU model is displayed a datasheet with additional technical information has to be in a right part of the webpage. For example, I have: Intel Core i7-3840QM ( Ivy Bridge / 4 cores / 8 logical CPUs / ark.intel.com/compare/70846 ) and these are data for all cache lines: Size of L3 Cache = 8MB ( shared between all cores for data & instructions ) Size of L2 Cache = 1MB ( 256KB per core / shared for data & instructions ) Size of L1 Cache = 256KB ( 32KB per core for data & 32KB per core for instructions )
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Bernard
Valued Contributor I
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It is not stated explicitly in Intel documentation.

Btw ISM on page 580 table 3-17 provides some info related to thread starter question, here is a short excerpt from this table :Bits 25-14: Maximum number of addressable IDs for logical processors sharing this cache**, ***

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SergeyKostrov
Valued Contributor II
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Here is update... L2 and L1 cache lines are shared between two Logical Processors, and L3 cache line is shared between all Logical Processors. Take a look at a Figure 2-8. Intel Core i7 Processor in Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 1: Basic Architecture on a page 45.
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SergeyKostrov
Valued Contributor II
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And one more thing: L2 and L1 cache lines are Not shared between Cores.
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Bernard
Valued Contributor I
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Thanks for the info.It seems that I started my search from wrong page:)

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SergeyKostrov
Valued Contributor II
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I'd like to correct my previous statement. >>>>...does Ivy Bridge (i7 3630qm) share L1 data cache between logical processors?.. >> >>I don't think so... L2 and L1 cache lines are shared between two Logical Processors and Not shared between all the rest Cores.
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