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

Table Of Contents
Vol. 3 A-197
PERFORMANCE-MONITORING EVENTS
14H CYCLES_DIV_
BUSY
00H Number of cycles during
which the divider is busy,
and cannot accept new
divides.
This includes integer and
FP divides, FPREM,
FPSQRT, etc. and is
speculative.
Counter 0 only.
Memory
Ordering
03H LD_BLOCKS 00H Number of load
operations delayed due
to store buffer blocks.
Includes counts caused
by preceding stores
whose addresses are
unknown, preceding
stores whose addresses
are known but whose
data is unknown, and
preceding stores that
conflicts with the load
but which incompletely
overlap the load.
04H SB_DRAINS 00H Number of store buffer
drain cycles.
Incremented every cycle
the store buffer is
draining.
Draining is caused by
serializing operations like
CPUID, synchronizing
operations like XCHG,
interrupt
acknowledgment, as well
as other conditions (such
as cache flushing).
Table A-18. Events That Can Be Counted with the P6 Family Performance-
Monitoring Counters (Contd.)
Unit
Event
Num.
Mnemonic Event
Name
Unit
Mask Description Comments