Errata
48
Specification Update
AN96.
Erratum removed
AN97.
Performance Monitoring Event SIMD_UOP_TYPE_EXEC.MUL Is
Counted Incorrectly for PMULUDQ Instruction
Problem:
Performance Monitoring Event SIMD_UOP_TYPE_EXEC.MUL (Event select 0B3H,
Umask 01H) counts the number of SIMD packed multiply micro-ops executed. The
count for PMULUDQ micro-ops might be lower than expected. No other instruction is
affected.
Implication:
The count value returned by the performance monitoring event
SIMD_UOP_TYPE_EXEC.MUL may be lower than expected. The degree of undercount
depends on actual occurrences of PMULUDQ instructions, while the counter is active.
Workaround:
None identified.
Status:
For the steppings affected, see the
AN98.
Storage of PEBS Record Delayed Following Execution of MOV SS or
STI
Problem:
When a performance monitoring counter is configured for PEBS (Precise Event Based
Sampling), overflow of the counter results in storage of a PEBS record in the PEBS
buffer. The information in the PEBS record represents the state of the next instruction
to be executed following the counter overflow. Due to this erratum, if the counter
overflow occurs after execution of either MOV SS or STI, storage of the PEBS record is
delayed by one instruction.
Implication:
When this erratum occurs, software may observe storage of the PEBS record being
delayed by one instruction following execution of MOV SS or STI. The state
information in the PEBS record will also reflect the one instruction delay.
Workaround:
None identified.
Status:
