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

Table Of Contents
Vol. 3 18-77
DEBUGGING AND PERFORMANCE MONITORING
record will be for the last tagged load operation which retired just before the PEBS
assist was invoked.
The load-latency information written into a PEBS record (see Table 18-21, bytes
AFH:98H) consists of:
Data Linear Address: This is the linear address of the target of the load
operation.
Latency Value: This is the elapsed cycles of the tagged load operation between
dispatch to GO, measured in processor core clock domain.
Data Source Encoding: The encoded value indicates the origin of the data
obtained by the load instruction. The encoding is shown in Table 18-22. In the
descriptions local memory refers to system memory physically attached to a
processor package, and remote memory referrals to system memory physically
attached to another processor package.
Table 18-22. Data Source Encoding for Load Latency Record
Encoding Description
0x0 Unknown L3 cache miss
0x1 Minimal latency core cache hit. This request was satisfied by the L1 data cache.
0x2 Pending core cache HIT. Outstanding core cache miss to same cache-line address
was already underway.
0x3 This data request was satisfied by the L2.
0x4 L3 HIT. Local or Remote home requests that hit L3 cache in the uncore with no
coherency actions required (snooping).
0x5 L3 HIT. Local or Remote home requests that hit the L3 cache and was serviced by
another processor core with a cross core snoop where no modified copies were
found. (clean).
0x6 L3 HIT. Local or Remote home requests that hit the L3 cache and was serviced by
another processor core with a cross core snoop where modified copies were found.
(HITM).
0x7 Reserved
0x8 L3 MISS. Local homed requests that missed the L3 cache and was serviced by
forwarded data following a cross package snoop where no modified copies found.
(Remote home requests are not counted).
0x9 Reserved
0xA L3 MISS. Local home requests that missed the L3 cache and was serviced by local
DRAM (go to shared state).
0xB L3 MISS. Remote home requests that missed the L3 cache and was serviced by
remote DRAM (go to shared state).