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POIntel TBB Code having different execution time in windows and linux
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  1. POIntel TBB Code having different execution time in windows and linux
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    copied!<p>I am trying to parallelize my code which is designing FIR Filter.For that i have chosen parallel_reduce .when i am executing code on windows it takes 15s and the same code when i am executing on linux it takes almost 2.5secs.In windows i am executing code on VS 2010 with Intel Performance libraries TBB Enabled and in linux i am compiling through terminal by including TBB libraries along with g++ compiler. As processor is same and code also will execute on same processor why this OS makes difference?</p> <p>Code which i have used is :</p> <pre><code>#include&lt;iostream&gt; #include "tbb/task_scheduler_init.h" #include "tbb/parallel_for.h" #include "tbb/blocked_range.h" #include "tbb/compat/thread" #include "tbb/parallel_reduce.h" #include &lt;math.h&gt; #include &lt;fstream&gt; using namespace tbb; using namespace std; #define pi 3.141593 #define FILTER_LEN 265 double coeffs[ FILTER_LEN ] = { 0.0033473431384214393,0.000032074683390218124,0.0033131082058404943,0.0024777666109278788, -0.0008968429179843104,-0.0031973449396977684,-0.003430943381749411,-0.0029796565504781646, -0.002770673157048994,-0.0022783059845596586,-0.0008531818129514857,0.001115432556294998, 0.0026079871108133294,0.003012423848769931,0.002461420635709332,0.0014154004589753215, 0.00025190669718400967,-0.0007608257014963959,-0.0013703600874774068,-0.0014133823230551277, -0.0009759556503342884,-0.00039687498737139273,-0.00007527524701314324,-0.00024181463305012626, -0.0008521761947454302,-0.00162618205097997,-0.002170446498273018,-0.002129903305507943, -0.001333859049002249,0.00010700092934983156,0.0018039564602637683,0.0032107930896349583, 0.0038325849735515363,0.003416201274366522,0.002060848732332109,0.00017954815260431595, -0.0016358832300944531,-0.0028402136847527387,-0.0031256650498727384,-0.0025374271571154713, -0.001438370315670195,-0.00035115295209013755,0.0002606730012030533,0.0001969569787142967, -0.00039635535951198597,-0.0010886127490608972,-0.0013530057243606405,-0.0008123200399262436, 0.0005730271959526784,0.0024419465938120906,0.004133717273258681,0.0049402122577746265, 0.0043879285604252714,0.002449549610687005,-0.00040283102645093463,-0.003337730734820209, -0.0054508346511294775,-0.006093057767824609,-0.005117609782189977,-0.0029293645861970417, -0.0003251033117661085,0.0018074390555649442,0.0028351284091668164,0.002623563404428517, 0.0015692864792199496,0.0004127664681096788,-0.00009249878881824428,0.0004690173244168184, 0.001964334172374759,0.0037256715492873485,0.004809640399145206,0.004395274594482053, 0.0021650921193604,-0.0014888595443799124,-0.005534807968511709,-0.008642334104607624, -0.009668950651149259,-0.008104732391434574,-0.004299972815463919,0.0006184612821881392, 0.005136551428636121,0.007907786753766152,0.008241212326068366,0.00634786595941524, 0.003235610213062744,0.00028882736660937287,-0.001320994685952108,-0.0011237433853145615, 0.00044213409507615003,0.0022057106517524255,0.00277593527678719,0.0011909915058737617, -0.0025807757230413447,-0.007497632882437637,-0.011739520895818884,-0.013377018279057393, -0.011166543231844196,-0.005133056165990026,0.0032948631959114935,0.011673660427968408, 0.017376415708412904,0.018548938130314566,0.014811760899506572,0.007450782505155853, -0.001019540069785369,-0.007805775815783898,-0.010898333714715424,-0.00985364043415772, -0.005988406030111452,-0.001818560524968024,0.000028552677472614846,-0.0019938756495376363, -0.007477684025727061,-0.013989430449615033,-0.017870518868849213,-0.015639422062597726, -0.005624959109456065,0.010993528170353541,0.03001263681283932,0.04527492462846608, 0.050581340787164114,0.041949186532860346,0.019360612460662185,-0.012644336735920483, -0.0458782599058412,-0.07073838953156347,-0.0791205623455818,-0.06709535677423759, -0.03644544574795176,0.005505370370858695,0.04780486657828151,0.07898800597378192, 0.0904453420042807,0.07898800597378192,0.04780486657828151,0.005505370370858695, -0.03644544574795176,-0.06709535677423759,-0.0791205623455818,-0.07073838953156347, -0.0458782599058412,-0.012644336735920483,0.019360612460662185,0.041949186532860346, 0.050581340787164114,0.04527492462846608,0.03001263681283932,0.010993528170353541, -0.005624959109456065,-0.015639422062597726,-0.017870518868849213,-0.013989430449615033, -0.007477684025727061,-0.0019938756495376363,0.000028552677472614846,-0.001818560524968024, -0.005988406030111452,-0.00985364043415772,-0.010898333714715424,-0.007805775815783898, -0.001019540069785369,0.007450782505155853,0.014811760899506572,0.018548938130314566, 0.017376415708412904,0.011673660427968408,0.0032948631959114935,-0.005133056165990026, -0.011166543231844196,-0.013377018279057393,-0.011739520895818884,-0.007497632882437637, -0.0025807757230413447,0.0011909915058737617,0.00277593527678719,0.0022057106517524255, 0.00044213409507615003,-0.0011237433853145615,-0.001320994685952108,0.00028882736660937287, 0.003235610213062744,0.00634786595941524,0.008241212326068366,0.007907786753766152, 0.005136551428636121,0.0006184612821881392,-0.004299972815463919,-0.008104732391434574, -0.009668950651149259,-0.008642334104607624,-0.005534807968511709,-0.0014888595443799124, 0.0021650921193604,0.004395274594482053,0.004809640399145206,0.0037256715492873485, 0.001964334172374759,0.0004690173244168184,-0.00009249878881824428,0.0004127664681096788, 0.0015692864792199496,0.002623563404428517,0.0028351284091668164,0.0018074390555649442, -0.0003251033117661085,-0.0029293645861970417,-0.005117609782189977,-0.006093057767824609, -0.0054508346511294775,-0.003337730734820209,-0.00040283102645093463,0.002449549610687005, 0.0043879285604252714,0.0049402122577746265,0.004133717273258681,0.0024419465938120906, 0.0005730271959526784,-0.0008123200399262436,-0.0013530057243606405,-0.0010886127490608972, -0.00039635535951198597,0.0001969569787142967,0.0002606730012030533,-0.00035115295209013755, -0.001438370315670195,-0.0025374271571154713,-0.0031256650498727384,-0.0028402136847527387, -0.0016358832300944531,0.00017954815260431595,0.002060848732332109,0.003416201274366522, 0.0038325849735515363,0.0032107930896349583,0.0018039564602637683,0.00010700092934983156, -0.001333859049002249,-0.002129903305507943,-0.002170446498273018,-0.00162618205097997, -0.0008521761947454302,-0.00024181463305012626,-0.00007527524701314324,-0.00039687498737139273, -0.0009759556503342884,-0.0014133823230551277,-0.0013703600874774068,-0.0007608257014963959, 0.00025190669718400967,0.0014154004589753215,0.002461420635709332,0.003012423848769931, 0.0026079871108133294,0.001115432556294998,-0.0008531818129514857,-0.0022783059845596586, -0.002770673157048994,-0.0029796565504781646,-0.003430943381749411,-0.0031973449396977684, -0.0008968429179843104,0.0024777666109278788,0.0033131082058404943,0.000032074683390218124, 0.0033473431384214393 }; class SumFoo { double* my_a; public: double sum; static int count; int ip,nip; void operator( )( const blocked_range&lt;size_t&gt;&amp; r ) { double *a = my_a; // cout&lt;&lt;"id of thread is \t"&lt;&lt;this_thread::get_id()&lt;&lt;endl; // cout&lt;&lt;"r.begin is "&lt;&lt;r.begin()&lt;&lt;"\t r.end is "&lt;&lt;r.end()&lt;&lt;endl; ip=( FILTER_LEN - 1 + (SumFoo::count)); for( size_t k=r.begin(); k!=r.end( ); ++k ) { nip=ip-k; sum+= ((coeffs[k]) * (a[nip])); } } SumFoo( SumFoo&amp; x, split ) : my_a(x.my_a), sum(0) { //cout&lt;&lt;"split Constructor called"&lt;&lt;endl; } void join( const SumFoo&amp; y ) { // cout&lt;&lt;"Joining all the sums"&lt;&lt;endl; sum+=y.sum; } SumFoo(double a[] ) :my_a(a), sum(0) { // cout&lt;&lt;"Constructor called"&lt;&lt;endl; } }; void ParallelSumFoo(double *a, size_t n ,ofstream &amp;o) { SumFoo sf(a); for(int j=264;j&lt;150264;j++) { SumFoo::count=j-264; parallel_reduce(blocked_range&lt;size_t&gt;(0,265), sf,auto_partitioner() ); o&lt;&lt;j&lt;&lt;","&lt;&lt;sf.sum&lt;&lt;endl; } } int SumFoo::count=0; int main() { ofstream o("400hzreduce.csv"); double *buffer=new double[150264]; fill_n(buffer,150264,0); tick_count t0=tick_count::now(); for(int i=264;i&lt;150264;i++) { buffer[i] = sin(400 * (2 * pi) * (i / 5000.0)); o&lt;&lt;i&lt;&lt;","&lt;&lt;buffer[i]&lt;&lt;endl; } cout&lt;&lt;fixed; ParallelSumFoo(buffer,150264,o); tick_count t1=tick_count::now(); double t9=(t1-t0).seconds(); cout&lt;&lt;"Time Taken for parallel execution is \t"&lt;&lt;t9&lt;&lt;"seconds"&lt;&lt;endl; } </code></pre> <p>Please help in finding where i am getting wrong?</p>
 

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