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

A-208 Vol. 3
PERFORMANCE-MONITORING EVENTS
16H INSTRUCTIONS_
EXECUTED
Number of instructions
executed (up to two per
clock)
Invocations of a fault handler are
considered instructions. All hardware
and software interrupts and
exceptions will also cause the count
to be incremented. Repeat prefixed
string instructions will only
increment this counter once despite
the fact that the repeat loop
executes the same instruction
multiple times until the loop criteria
is satisfied.
This applies to all the Repeat string
instruction prefixes (i.e., REP, REPE,
REPZ, REPNE, and REPNZ). This
counter will also only increment once
per each HLT instruction executed
regardless of how many cycles the
processor remains in the HALT state.
17H INSTRUCTIONS_
EXECUTED_ V PIPE
Number of instructions
executed in the V_pipe
The event indicates the
number of instructions
that were paired.
This event is the same as the 16H
event except it only counts the
number of instructions actually
executed in the V-pipe.
18H BUS_CYCLE_
DURATION
Number of clocks while
a bus cycle is in progress
This event measures
bus use.
The count includes HLDA, AHOLD,
and BOFF# clocks.
19H WRITE_BUFFER_
FULL_STALL_
DURATION
Number of clocks while
the pipeline is stalled
due to full write buffers
Full write buffers stall data memory
read misses, data memory write
misses, and data memory write hits
to S-state lines. Stalls on I/O
accesses are not included.
1AH WAITING_FOR_
DATA_MEMORY_
READ_STALL_
DURATION
Number of clocks while
the pipeline is stalled
while waiting for data
memory reads
Data TLB Miss processing is also
included in the count. The pipeline
stalls while a data memory read is in
progress including attempts to read
that are not bypassed while a line is
being filled.
Table A-19. Events That Can Be Counted with Pentium Processor
Performance-Monitoring Counters (Contd.)
Event
Num.
Mnemonic Event
Name Description Comments