поддержка Intel Tremont core PMU (support for Intel Tremont core PMU)
Имя (Name)
libpfm_intel_tmt - support for Intel Tremont core PMU
Синопсис (Synopsis)
#include <perfmon/pfmlib.h>
PMU name: tmt
PMU desc: Intel Tremont
Описание (Description)
The library supports the Intel Tremont core PMU.
Модификаторы (Modifiers)
The following modifiers are supported on Intel Tremont
processors:
u Measure at user level which includes privilege levels 1,
2, 3. This corresponds to PFM_PLM3. This is a boolean
modifier.
k Measure at kernel level which includes privilege level 0.
This corresponds to PFM_PLM0. This is a boolean modifier.
i Invert the meaning of the event. The counter will now
count cycles in which the event is not occurring. This is
a boolean modifier
e Enable edge detection, i.e., count only when there is a
state transition from no occurrence of the event to at
least one occurrence. This modifier must be combined with
a counter mask modifier (m) with a value greater or equal
to one. This is a boolean modifier.
c Set the counter mask value. The mask acts as a threshold.
The counter will count the number of cycles in which the
number of occurrences of the event is greater or equal to
the threshold. This is an integer modifier with values in
the range [0:255].
Cобытия отклика вне ядра (Offcore_response events)
Intel Tremont provides two offcore_response events:
OFFCORE_RESPONSE_0 and OFFCORE_RESPONSE_1. The OCR event is
aliased to OFFCORE_RESPONSE_0.
Those events need special treatment in the performance monitoring
infrastructure because each event uses an extra register to store
some settings. Thus, in case multiple offcore_response events are
monitored simultaneously, the kernel needs to manage the sharing
of that extra register.
The offcore_response event is exposed as a normal event by the
library. The extra settings are exposed as regular umasks. The
library takes care of encoding the events according for the
underlying kernel interface.
On Intel Tremont, it is not possible to combine the request,
supplier, snoop, fields anymore to avoid invalid combinations. As
such, the umasks provided by the library are the only ones
supported and validated.
