Nehalem

Architecture specific notes for Intel Nehalem

Performance groups

Intel Nehalem Performance groups

Events

The input file for the events on Intel Nehalem can be found here.

Counters

• Core-local counters
  • Fixed-purpose counters
  • General-purpose counters
• Socket-wide counters
  • Uncore fixed-purpose counters
  • Uncore general-purpose counters

Core-local counters

Fixed-purpose counters

Since the Core2 microarchitecture, Intel® provides a set of fixed-purpose counters. Each can measure only one specific event.

Counters

Counter name	Event name
FIXC0	INSTR_RETIRED_ANY
FIXC1	CPU_CLK_UNHALTED_CORE
FIXC2	CPU_CLK_UNHALTED_REF

##### Available Options

Option	Argument	Description	Comment
anythread	N	Set bit 2+(index*4) in config register
kernel	N	Set bit (index*4) in config register

#### General-purpose counters The Intel® Nehalem microarchitecture provides 4 general-purpose counters consisting of a config and a counter register. ##### Counters

Counter name	Event name
PMC0	*
PMC1	*
PMC2	*
PMC3	*

##### Available Options

Option	Argument	Description	Comment
edgedetect	N	Set bit 18 in config register
kernel	N	Set bit 17 in config register
anythread	N	Set bit 21 in config register
threshold	8 bit hex value	Set bits 24-31 in config register
invert	N	Set bit 23 in config register

Special handling for events

The Intel® Nehalem microarchitecture provides measuring of offcore events in PMC counters. Therefore the stream of offcore events must be filtered using the OFFCORE_RESPONSE registers. The Intel® Nehalem microarchitecture has one of those registers. Own filtering can be applied with the OFFCORE_RESPONSE_0_OPTIONS event. Only for those events two more counter options are available:

Option	Argument	Description	Comment
match0	8 bit hex value	Input value masked with 0xFF and written to bits 0-7 in the OFFCORE_RESPONSE register	Check the Intel® Software Developer System Programming Manual, Vol. 3, Chapter Performance Monitoring and https://download.01.org/perfmon/NHM-EP.
match0	8 bit hex value	Input value masked with 0xF7 and written to bits 8-15 in the OFFCORE_RESPONSE register	Check the Intel® Software Developer System Programming Manual, Vol. 3, Chapter Performance Monitoring and https://download.01.org/perfmon/NHM-EP.

Socket-wide counters

Uncore fixed-purpose counters

The Intel Nehalem architecture provides one fixed-purpose Uncore counter to measure the clock frequency of the Uncore.

Counters

Counter name	Event name
UPMCFIX	UNCORE_CLOCKTICKS

Uncore general-purpose counters

The Intel® Nehalem microarchitecture provides 8 general-purpose counters consisting of a config and a counter register.

Counters

Counter name	Event name
UPMC0	*
UPMC1	*
UPMC2	*
UPMC3	*
UPMC4	*
UPMC5	*
UPMC6	*
UPMC7	*

##### Available Options

Option	Argument	Description	Comment
edgedetect	N	Set bit 18 in config register
anythread	N	Set bit 21 in config register
threshold	8 bit hex value	Set bits 24-31 in config register
invert	N	Set bit 23 in config register
opcode	8 bit hex value	Set bits 40-47 in MSR_UNCORE_ADDR_OPCODE_MATCH register	Documented but register only available in Intel Westmere architecture. A list of valid opcodes can be found in the Intel® Software Developer System Programming Manual, Vol. 3, Chapter Performance Monitoring.
match0	40 bit physical memory address	Extract bits 3-39 from address and write them to bits 3-39 in MSR_UNCORE_ADDR_OPCODE_MATCH register	Documented but register only available in Intel Westmere architecture.