Intel E7-8891 v2 CM8063601377422 User Manual

Product codes
CM8063601377422
Page of 504
Intel
®
 Xeon
® 
Processor E7-2800/4800/8800 v2 Product Family
69
Datasheet Volume Two: Functional Description, February 2014
Performance Monitoring
11
Performance Monitoring
This chapter will provide an overview of the Intel Xeon processor E7 v2 product family 
performance monitoring (perfmon) features and describe how the architecture works at 
a high level.
11.1
Terminology
• UNIT: A UNIT means any non IA-Core unit supporting PerfMon including: Cbos, 
Home Agent (HA), Memory Controller (iMC), Intel QPI Agent, Ubox, and PCU. 
• PMI: Performance Monitoring Interrupt - triggered by counter overflows and used 
to cause PerfMon counters in selected cores to stall and to trigger software 
interrupt handlers to process the information stores in the perfmons.
• Counter: A counter is a physical register inside of the uncore that can be 
programmed to count a specific “event.” 
• Event: An event is what you program a counter to count. For example, one might 
program a “counter” to count the “LLC hits” event.
11.2
Infrastructure
The Intel Xeon processor E7 v2 product family uncore performance monitor utilizes a 
distributed design. There are essential PerfMon counter blocks stamped throughout the 
uncore which have numerous event signals fed into them and control logic to select 
which events to count and how to count.
There are two global Registers that exist inside of the counter reporting agent. The 
“Global Control” Register controls how the Uncore Perfmon behaves at a global level. 
The “Global Status” CR provides information about the status of the system. 
Each unit has a single “Unit Control Register” that can be used to perform global 
operations across the unit such as freezing and resetting the counters. They will also 
have a “Unit Status” register that provides information about which register 
overflowed.
Some units have a separate special control register that allow for special event 
filtering/control within the unit.
11.3
PCU PerfMon
11.3.1
High-Level Overview
Perfmon for the PCU is very similar to the standard uncore perfmon used throughout 
the Intel Xeon processor E7 v2 product family uncore. The PCU perfmon has some 
adaptations from the standard uncore perfmon to enable some special usage models 
and to push some of the complexity out of the hardware and into PCU microcode. 
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