英语翻译2.3 Last Stream PredictorThe third stage uses a simple l

英语翻译
2.3 Last Stream Predictor
The third stage uses a simple last value predictor as
shown in Fig.3 to exploit redundancy in the SI trace
component caused by repeating sequences of stream indices.
A linear predictor table with NP entries is indexed by
a hash function that is based on the history of previous
stream indices.If the selected predictor entry matches the
incoming stream index,we have an LSP hit.Otherwise,
we have an LSP miss,and the selected predictor entry is
updated with the incoming stream index.The hit/miss
information (one bit,a ‘0’ for a miss and a ‘1’ for a hit)
and,in case of an LSP miss,SI (log2(NSET*NWAYS) bits) are
forwarded to the trace encoder.
The compression ratio achievable by the LSP stage
alone,CR(LSP),can be calculated as shown in (2).It depends
on the stream index size and the LSP hit rate,
hrLSP.The maximum compression ratio that can be
achieved by this stage is log2(NSET*NWAY).The design
space exploration for the last stream predictor includes
determining a good hash function and a number of entries
in the predictor NP.