Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
18-136 Vol. 3
DEBUGGING AND PERFORMANCE MONITORING
18.24.1 Overview of Performance Monitoring with L3/Caching Bus
Controller
The facility for monitoring events consists of a set of dedicated model-specific
registers (MSRs). There are eight event select/counting MSRs that are dedicated to
counting events associated with specified microarchitectural conditions. Program-
ming of these MSRs requires using RDMSR/WRMSR instructions with 64-bit values.
In addition, an MSR MSR_EMON_L3_GL_CTL provides simplified interface to control
freezing, resetting, re-enabling operation of any combination of these event
select/counting MSRs.
The eight MSRs dedicated to count occurrences of specific conditions are further
divided to count three sub-classes of microarchitectural conditions:
Two MSRs (MSR_EMON_L3_CTR_CTL0 and MSR_EMON_L3_CTR_CTL1) are
dedicated to counting GBSQ events. Up to two GBSQ events can be programmed
and counted simultaneously.
Two MSRs (MSR_EMON_L3_CTR_CTL2 and MSR_EMON_L3_CTR_CTL3) are
dedicated to counting GSNPQ events. Up to two GBSQ events can be
programmed and counted simultaneously.
Figure 18-54. Block Diagram of Intel Xeon Processor 7100 Series
SDI interface
Processor core
SDI interface
Processor core
L3
GBSQ, GSNPQ,
GINTQ, ...
FSB
SDI
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