Ok, I see your point, but I'm considering the "max" number of BP accesses.
Regards, Fernando -- Fernando A. Endo, PhD student and researcher Université de Grenoble, UJF France 2013/4/25 Arthur Perais <[email protected]> > Isn't it rather "fetchWidth or until the first taken branch"? > > Le 25/04/2013 11:10, Fernando Endo a écrit : > > Hello, > > I'm using the stable gem5 (jun 2012). > > Taking a look at the DefaultFetch<Impl>::fetch method > (src/cpu/o3/fetch_impl.hh), I found that the branch predictor can be > accessed more than once per cycle (function lookupAndUpdateNextPC(.)): > > // Loop through instruction memory from the cache. > // Keep issuing while fetchWidth is available and branch is not > // predicted taken > while (numInst < fetchWidth && !predictedBranch) { > > ... > > // Extract as many instructions and/or microops as we can from > // the memory we've processed so far. > do { > ... > predictedBranch |= lookupAndUpdateNextPC(instruction, nextPC); > ... > } while ((curMacroop || decoder[tid]->instReady()) && numInst < > fetchWidth); > > ... > } > > So, it seems for me that the max number of accesses per fetch tick is > equal the fetchWidth = 3. Is it or I'm missing something? > > Considering fetchToDecodeDelay=3, the number of branch predictor acesses > per cycle is exactly 1. > > Thanks for your help, > > -- > Fernando A. Endo, PhD student and researcher > > Université de Grenoble, UJF > France > > > > _______________________________________________ > gem5-users mailing > [email protected]http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > > > > _______________________________________________ > gem5-users mailing list > [email protected] > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >
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