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

Table Of Contents
A-216 Vol. 3
PERFORMANCE-MONITORING EVENTS
37H MISPREDICTED_
OR_
UNPREDICTED_
RETURNS
(Counter 1)
Number of returns
predicted incorrectly or
not predicted at all
The count is the difference between
the total number of executed returns
and the number of returns that were
correctly predicted. Only RET
instructions are counted (for
example, IRET instructions are not
counted).
37H PREDICTED_
RETURNS
(Counter 1)
Number of predicted
returns (whether they
are predicted correctly
and incorrectly
Only RET instructions are counted
(for example, IRET instructions are
not counted).
38H MMX_MULTIPLY_
UNIT_INTERLOCK
(Counter 0)
Number of clocks the
pipe is stalled since the
destination of previous
MMX multiply
instruction is not ready
yet
The counter will not be incremented
if there is another cause for a stall.
For each occurrence of a multiply
interlock, this event will be counted
twice (if the stalled instruction
comes on the next clock after the
multiply) or by once (if the stalled
instruction comes two clocks after
the multiply).
38H MOVD/MOVQ_
STORE_STALL_
DUE_TO_
PREVIOUS_MMX_
OPERATION
(Counter 1)
Number of clocks a
MOVD/MOVQ instruction
store is stalled in D2
stage due to a previous
MMX operation with a
destination to be used in
the store instruction.
39H RETURNS
(Counter 0)
Number or returns
executed.
Only RET instructions are counted;
IRET instructions are not counted.
Any exception taken on a RET
instruction and any interrupt
recognized by the processor on the
instruction boundary prior to the
execution of the RET instruction will
also cause this counter to be
incremented.
39H Reserved
Table A-19. Events That Can Be Counted with Pentium Processor
Performance-Monitoring Counters (Contd.)
Event
Num.
Mnemonic Event
Name Description Comments