Commit ba1e2f36 authored by Alan Marchiori's avatar Alan Marchiori
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brtrace.out

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global_pred.py

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class global_pht:

    def __init__(self, num_history_bits = 3):

        self.num_bits = num_history_bits

        

        self.num_index = 2**self.num_bits

        self.shift_register = self.num_index - 1         

        

        self.bin_fmt = "{{:0{}b}}".format(self.num_bits)

        self.counters = [ 'T' for i in range (self.num_index)]

        

    def predict(self, pc, target, outcome, verbose, learn = True):

                

        result = self.counters[self.shift_register]

                

        if verbose and learn:

            print ("predicting PC = 0x{:x}, branch history = ".format(pc) + \

                   self.bin_fmt.format(self.shift_register) + \

                   " outcome = {}".format(outcome))

            

            

            tag = {True: '<===',

                   False: ''}

            msg = {False: {True: "", False: ""},

                   True: {True: " (correct)",

                          False: " (MISSPREDICT)"}}

            for i in range (self.num_index):

                                

                print ("PHT[" + self.bin_fmt.format(i) + "] = {} {}{}".format(self.counters[i],

                                                                            tag[i == self.shift_register],

                                                                            msg[i == self.shift_register][result == outcome]))

                

            

        



        if learn:

            self.counters[self.shift_register] = outcome

        

        self.shift_register = ((self.shift_register << 1) & (self.num_index - 1))

        if outcome == 'T':

            self.shift_register |= 1

        

        return result
 
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hybrid_correlating.py

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from twolevel import correlation_register

from local import saturating_counter





class hybrid_correlating_predictor():

    def __init__(self, global_history_bits = 2, local_pc_bits = 3):        

        self.global_indexes = 2**global_history_bits        

        self.local_indexes = 2**local_pc_bits

        self.bin_fmt = "{{:0{}b}}".format(global_history_bits)

        

    def predict(self, pc, target, outcome, verbose):        

        """TODO: complete this"""

        

            

        return "T"

    

    
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local.py

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Original line number Diff line number Diff line 
import math

class saturating_counter(): 

    pred = ['N', 'N', 'T', 'T']   

    def __init__(self):

        self.value = 3

    def increment(self):        

        if self.value  < 3:

            self.value += 1 

    def decrement(self):

        if self.value > 0:

            self.value -= 1

    def predict(self):

        return saturating_counter.pred[self.value]

    def __str__(self):

        return "{:02b} ({})".format(self.value, saturating_counter.pred[self.value])

    

class local_bht:

    def __init__(self, num_index_bits = 3):

        self.num_index = 2**num_index_bits        

        self.counters = [saturating_counter() for i in range(self.num_index)]

        

        # compute the correct number of significant digits

        self.bin_fmt ="{{:{}d}}".format(math.ceil(math.log10(self.num_index))) 

        

    def predict(self, pc, target, outcome, verbose):        

        i = (pc//4) % self.num_index

        result = self.counters[i].predict()



        if verbose:

            print ("predict PC = {:x}, index = {:d}, outcome = {}".format(pc, i, outcome))

            tag = {True: '<===',

                   False: ''}

            msg = {False: {True: "", False: ""},

                   True: {True: " (correct)",

                          False: " (MISSPREDICT)"}}

            

            for x in range (self.num_index):                                

                print ("BHT[" + self.bin_fmt.format(x) + "] = {} {}{}".format(self.counters[x],

                                                                            tag[i == x],

                                                                            msg[i == x][result == outcome]))



        if outcome == 'T':

            self.counters[i].increment()

        else:

            self.counters[i].decrement()

                     

        return result
 
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predict.py

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from static import static_predictor

from local import local_bht

from global_pred  import global_pht # global is a reserved word, cannot use as module name

from twolevel import twolevel_predictor

from hybrid_correlating import hybrid_correlating_predictor

from tournament import tournament_predictor



def predict(lines, verbose = False, predictor = static_predictor()):

    """Input is a generator which yields triples: (PC, branch target, [T]aken / [N]ot taken

    """

    

    stats = {True:0, 

             False:0}

    msg = {True: '',

           False: '*MISSPREDICT*'}

    for pc, target, outcome in lines:

        

        #if verbose:

        #    print()

        #    print ("-"*30)

        prd = predictor.predict(pc, target, outcome, verbose)

        

        if verbose:

            print ("0x{:x} --> 0x{:x}: pred = {} actual = {} {}".format(pc,

                                                                        target,

                                                                        prd,

                                                                        outcome,

                                                                        msg[prd == outcome]))        

        #if verbose:

        #    print ("+"*30)

        stats[prd == outcome] +=  + 1

        

    print ("Correct: {}, misspredict: {}, Accuracy: {:4.2f}%".format(stats[True],

                                                                     stats[False],

                                                                     100*stats[True]/(sum(stats.values()))))

    

    

if __name__ == "__main__":

        

    branches =  """0x31c1e011c8 0x31c1e011b0 T

 0x31c1e011c2 0x31c1e011f0 N

 0x31c1e011c8 0x31c1e011b0 T

 0x31c1e011c2 0x31c1e011f0 N

 0x31c1e011c8 0x31c1e011b0 T

 0x31c1e011c2 0x31c1e011f0 N

 0x31c1e011c8 0x31c1e011b0 T

 0x31c1e011c2 0x31c1e011f0 N

 0x31c1e011c8 0x31c1e011b0 N

 0x31c1e011d4 0x31c1e014d0 N

 0x31c1e011ee 0x31c1e011c4 T

 0x31c1e011c8 0x31c1e011b0 N

 0x31c1e011d4 0x31c1e014d0 N

 0x31c1e011ee 0x31c1e011c4 T

 0x31c1e011c8 0x31c1e011b0 T

 0x31c1e011c2 0x31c1e011f0 N

 0x31c1e011c8 0x31c1e011b0 N

 0x31c1e011d4 0x31c1e014d0 N

 0x31c1e011ee 0x31c1e011c4 T

 0x31c1e011c8 0x31c1e011b0 N

 0x31c1e011d4 0x31c1e014d0 N

 0x31c1e011ee 0x31c1e011c4 T

 0x31c1e011c8 0x31c1e011b0 N"""

    

    def parts_to_ints(parts):

        return ( int(parts[0],16), int(parts[1],16), parts[2] )     

    

    # use this line if you want to read from a file.

    #lines = open('brtrace.out').readlines()

    lines = branches.split('\n')    

    

    verb = True

    

    # which predictor or predictors you want to run...

    predictors = 'static'    

    

    if 'static' in predictors:

        for predictor, string in ( (static_predictor(), 'Static'), ):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')

            predict (s, verb, predictor)

      

        print ("="*60)        

    

    if 'local' in predictors:

        #for predictor, string in (

                                  #(local_bht(i), '2-bit local BHT n={:2d}'.format(i)) for i in range (1, 4)  ):

                                  

        for predictor, string in ((local_bht(3), '2-bit local BHT with {} entries'.format(2**3)),):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')            

            predict (s, verb, predictor)

    

        print ("="*60)

        

    if 'global' in predictors:

        #for predictor, string in (

         #                         (global_pht(i), 'Global PHT n={:2d}'.format(i)) for i in range (1, 4)  ):

        for predictor, string in ( (global_pht(3), 'Global PHT with {} entries'.format(2**3)), ):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')            

            predict (s, verb, predictor)          

            

        print ("="*60)

        

    if 'twolevel' in predictors:

        for predictor, string in ( (twolevel_predictor(3,3), 'Two-level with {} entries and {} counters'.format(8,8)), ):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')            

            predict (s, verb, predictor)          

            

        print ("="*60)

   

    if 'hybrid_correlating' in predictors:

       for predictor, string in ( (hybrid_correlating_predictor(2,3), 

                                   'Hybrid correlating with global {} bit shift register and {} BHT counters'.format(2,2**3)), ):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')            

            predict (s, verb, predictor)          

       print ("="*60)

       

    if 'tournament' in predictors:

       for predictor, string in ( (tournament_predictor(3, 3, 3), 

                                   'tournament predictor {} entry bht and {} bit shift register'.format(8,8)), ):

            s = (x.strip().split(' ') for x in lines)

            s = (parts_to_ints(x) for x in s)         

            print (string, ': ')            

            predict (s, verb, predictor)          

       print ("="*60)        

        

        
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