Good job, Daniel! -- Alexey A. Ivanov Intel Middleware Product Division
>-----Original Message----- >From: Daniel Fridlender [mailto:[EMAIL PROTECTED] >Sent: Tuesday, November 07, 2006 3:22 AM >To: harmony-dev@incubator.apache.org >Subject: Re: [classlib][java.math] optimization of BigInteger.modPow and >BigInteger.pow > >Hi Alexey, > >yes we often tested the speed in our several attempts to improve >performance. Comparing modPow before and after this new patch gave us >the following figures: > >size before after >16 5.636e+05 6.351e+05 >32 9.727e+04 1.293e+05 >48 3.225e+04 4.623e+04 >64 1.436e+04 2.148e+04 >128 1941 3114 >192 590 970 >256 252 420 >384 75 127 >512 32 55 > >where the first column shows the size of the arguments in bytes and >the other two the number of modPow operations per 100 seconds before >and after the patch. > >The method modPow is used in cryptography, we tested several >cryptographic algorithms obtaining in all cases figures in favor of >the optimized version (the one in the patch). >For instance, for RSA key generation we obtained: > >size before after >512 3,00 2,06 >1024 20,17 13,58 >2048 280,38 149,48 > >where the first column shows the length of the key in bits and the >other two the time in seconds taken to perform 30 iterations of the >key generation algorithm before and after the patch. > >Thanks, > >Daniel > >On 11/3/06, Alexey Petrenko <[EMAIL PROTECTED]> wrote: >> Hi, Daniel. >> >> Great job! >> >> Have you made any performance testing to understand how much the patch >> increases the speed of the methods? >> >> SY, Alexey >> >> 2006/11/3, Daniel Fridlender <[EMAIL PROTECTED]>: >> > Hi, >> > >> > We have submitted in http://issues.apache.org/jira/browse/HARMONY-1981 >> > an optimization of BigInteger methods modPow and pow. >> > >> > The optimization in modPow was achieved by introducing sliding windows >> > instead of the square-and-multiply method. Some gain was obtained >> > also from an optimized Montgomery multiplication used for computing >> > squares. >> > >> > The method pow was optimized accordingly by improving the computation >> > of squares. >> > >> > Thanks >> > >> > Daniel >> > >>
