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

Table Of Contents
Vol. 3 A-187
PERFORMANCE-MONITORING EVENTS
Table A-18. Events That Can Be Counted with the P6 Family Performance-
Monitoring Counters
Unit
Event
Num.
Mnemonic Event
Name
Unit
Mask Description Comments
Data Cache
Unit (DCU)
43H DATA_MEM_REFS 00H All loads from any
memory type. All stores
to any memory type.
Each part of a split is
counted separately. The
internal logic counts not
only memory loads and
stores, but also internal
retries.
80-bit floating-point
accesses are double
counted, since they are
decomposed into a 16-bit
exponent load and a
64-bit mantissa load.
Memory accesses are
only counted when they
are actually performed
(such as a load that gets
squashed because a
previous cache miss is
outstanding to the same
address, and which finally
gets performed, is only
counted once).
Does not include I/O
accesses, or other
nonmemory accesses.
45H DCU_LINES_IN 00H Total lines allocated in
DCU
46H DCU_M_LINES_IN 00H Number of M state lines
allocated in DCU
47H DCU_M_LINES_
OUT
00H Number of M state lines
evicted from DCU
This includes evictions
via snoop HITM,
intervention or
replacement.