19-158 Vol. 3B
PERFORMANCE-MONITORING EVENTS
30H
See
and
L2_REJECT_BUSQ
Rejected L2 cache
requests.
This event indicates that a pending L2 cache request that
requires a bus transaction is delayed from moving to the bus
queue. Some of the reasons for this event are:
- The bus queue is full.
- The bus queue already holds an entry for a cache line in the
same set.
The number of events is greater or equal to the number of
requests that were rejected.
- For this core or both cores.
- Due to demand requests and L2 hardware prefetch requests
together, or separately.
- Of accesses to cache lines at different MESI states.
32H
See
L2_NO_REQ
Cycles no L2 cache
requests are pending.
This event counts the number of cycles that no L2 cache
requests are pending.
3AH
00H
EIST_TRANS
Number of Enhanced
Intel SpeedStep(R)
Technology (EIST)
transitions.
This event counts the number of Enhanced Intel SpeedStep(R)
Technology (EIST) transitions that include a frequency change,
either with or without VID change. This event is incremented
only while the counting core is in C0 state. In situations where
an EIST transition was caused by hardware as a result of CxE
state transitions, those EIST transitions will also be registered
in this event.
Enhanced Intel Speedstep Technology transitions are commonly
initiated by OS, but can be initiated by HW internally. For
example: CxE states are C-states (C1,C2,C3…) which not only
place the CPU into a sleep state by turning off the clock and
other components, but also lower the voltage (which reduces
the leakage power consumption). The same is true for thermal
throttling transition which uses Enhanced Intel Speedstep
Technology internally.
3BH
C0H
THERMAL_TRIP
Number of thermal
trips.
This event counts the number of thermal trips. A thermal trip
occurs whenever the processor temperature exceeds the
thermal trip threshold temperature. Following a thermal trip,
the processor automatically reduces frequency and voltage.
The processor checks the temperature every millisecond, and
returns to normal when the temperature falls below the
thermal trip threshold temperature.
Table 19-26. Non-Architectural Performance Events for 45 nm, 32 nm Intel® Atom™ Processors (Contd.)
Event
Num.
Umask
Value
Event Name
Definition
Description and Comment