19-208 Vol. 3B

PERFORMANCE-MONITORING EVENTS

6EH

BUS_TRAN_

BURST

00H 

(Self)
20H 

(Any)

Number of completed burst transactions.

70H

BUS_TRAN_ANY

00H 

(Self)
20H 

(Any)

Number of all completed bus transactions.
Address bus utilization can be calculated 

knowing the minimum address bus 

occupancy.
Includes special cycles, etc.

6FH

BUS_TRAN_MEM

00H 

(Self)
20H 

(Any)

Number of completed memory transactions.

64H

BUS_DATA_RCV

00H 

(Self)

Number of bus clock cycles during which this 

processor is receiving data.

61H

BUS_BNR_DRV

00H 

(Self)

Number of bus clock cycles during which this 

processor is driving the BNR# pin.

7AH

BUS_HIT_DRV

00H 

(Self)

Number of bus clock cycles during which this 

processor is driving the HIT# pin.

Includes cycles due to snoop stalls.
The event counts correctly, but 

BPMi (breakpoint monitor) pins 

function as follows based on the 

setting of the PC bits (bit 19 in the 

PerfEvtSel0 and PerfEvtSel1 

registers):
• If the core-clock-to- bus-clock 

ratio is 2:1 or 3:1, and a PC bit is 

set, the BPMi pins will be 

asserted for a single clock when 

the counters overflow.

• If the PC bit is clear, the 

processor toggles the BPMi pins 

when the counter overflows.

• If the clock ratio is not 2:1 or 3:1, 

the BPMi pins will not function 

for these performance-

monitoring counter events.

7BH

BUS_HITM_DRV

00H 

(Self)

Number of bus clock cycles during which this 

processor is driving the HITM# pin.

Includes cycles due to snoop stalls.
The event counts correctly, but 

BPMi (breakpoint monitor) pins 

function as follows based on the 

setting of the PC bits (bit 19 in the 

PerfEvtSel0 and PerfEvtSel1 

registers):
• If the core-clock-to- bus-clock 

ratio is 2:1 or 3:1, and a PC bit is 

set, the BPMi pins will be 

asserted for a single clock when 

the counters overflow.

Table 19-37.  Events That Can Be Counted with the P6 Family Performance-Monitoring Counters (Contd.)

Unit

Event 

Num.

Mnemonic Event 

Name

Unit 

Mask Description

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