Re: [eigen] two things |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] two things*From*: Benoît Jacob <jacob@xxxxxxxxxxxxxxx>*Date*: Thu, 26 Jun 2008 18:23:29 +0200

By the way, looking at benchVecAdd.cpp... a gigaflop is probably 10^9 flops, not 2^30 flops as you coded it... these results already aren't so shining (as you noted they'd already be much better with peeling) so let's not make them even worse! :) Benoit On Thursday 26 June 2008 18:12:24 Benoît Jacob wrote: > Here is the result here after revision 824739 introducing packet(int): > > 2.30471s 0.646553 GFlops > 400 x 400 2.51917s 0.59151 GFlops > 320 x 500 3.00975s 0.495097 GFlops > 256 x 625 2.92007s 0.510302 GFlops > 250 x 640 2.9007s 0.513709 GFlops > 200 x 800 2.9415s 0.506583 GFlops > 160 x 1000 2.90815s 0.512393 GFlops > 128 x 1250 2.73835s 0.544166 GFlops > 125 x 1280 2.889s 0.515789 GFlops > 100 x 1600 2.92752s 0.509003 GFlops > 80 x 2000 2.86383s 0.520322 GFlops > 64 x 2500 2.9053s 0.512896 GFlops > 50 x 3200 2.90992s 0.512081 GFlops > 40 x 4000 2.90439s 0.513056 GFlops > 32 x 5000 2.80648s 0.530955 GFlops > 25 x 6400 2.85519s 0.521896 GFlops > 20 x 8000 2.79833s 0.532503 GFlops > 16 x 10000 2.8511s 0.522646 GFlops > 10 x 16000 2.81542s 0.52927 GFlops > 8 x 20000 2.80733s 0.530795 GFlops > 5 x 32000 2.76623s 0.53868 GFlops > 4 x 40000 2.85234s 0.522418 GFlops > 2.80785s 0.530697 GFlops > > So, as expected, this problem is solved. > > > hand coded vector with loop peeling: > > 1.0101 sec 1.47521 GFlops > > > > VectorXf(400*400): > > 1.50368 0.990978 GFlops > > So it would be much worth peeling loops. Now that we have a real linear > path (and could also write a linear path in non-vectorized case) this will > be much easier and more efficient. > > Cheers, > > Benoit > > PS. There was a crash in benchVecAdd caused by ei_pload on non-aligned > address. It is tricky as of course with a bit of luck you could get three > aligned addresses in a row, especially on a 64 bit system like yours... > fixed in bench/.

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**References**:**[eigen] two things***From:*Benoît Jacob

**Re: [eigen] two things***From:*Gael Guennebaud

**Re: [eigen] two things***From:*Benoît Jacob

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