I think the reason for the performance difference is that 64bit quantities are being pushed around rather than 32bit ones. That would explain the ~2X difference in speed.
--Chris On Fri, Sep 16, 2011 at 11:32 PM, Sisyphus <[email protected]> wrote: > > ----- Original Message ----- From: "chm" <[email protected]> > To: "Sisyphus" <[email protected]> > Cc: "chm" <[email protected]>; <[email protected]> > Sent: Friday, September 16, 2011 9:14 PM > > Subject: Re: [Perldl] auto pthread performance gain > > >> On 9/16/2011 1:42 AM, Sisyphus wrote: >>> >>> >>> ----- Original Message ----- From: "chm" <[email protected]> >>> To: "Chris Marshall" <[email protected]> >>> Cc: <[email protected]> >>> Sent: Tuesday, September 13, 2011 9:01 PM >>> Subject: Re: [Perldl] auto pthread performance gain >>> >>> >>>> Running the :hisreswallclock version of t/pthread_auto.t >>>> on the original Athlon X2 Dual Core machine with the >>>> '$a **= 1.3' operation now shows a 2X speedup as hoped... >> >> >> The current test uses '$a += 1' and '$b += 1' as the >> computations. That is all memory and no computation. >> If you edit to use a more expensive operation like >> '$a **= 1.3' and '$b **= 1.3' you'll see more of a >> win. > > > Yes - "threaded" then consumes roughly half as many wallclock seconds as > "unthreaded". > Also, looking at Task Manager, I can see that both cores are used for the > "threaded" computation, whereas the "unthreaded" computation uses just the > one core. > > 64-bit perl 5.14.0, gcc-4.7.0: > threaded: 10.3323 wallclock secs > unthreaded: 19.6193 wallclock secs > threaded is 1.9 times faster > > 32-bit perl 5.14.0, gcc-3.4.5: > threaded: 4.20657 wallclock secs > unthreaded: 10.6451 wallclock secs > threaded is 2.53 times faster. > > 32-bit perl 5.14.0, gcc-4.5.2: > threaded: 3.33988 wallclock secs > unthreaded: 9.24037 wallclock secs > threaded is 2.77 times faster > > Interesting that the 64-bit perl is so much slower than the two 32-bit > perls. > > The mingw64.sf team also provide a 'winpthreads' package: > http://mingw-w64.svn.sourceforge.net/viewvc/mingw-w64/experimental/winpthreads/ > > I must try it out and see if it provides a better than 1.9x improvement for > the x64 build. > > Cheers, > Rob _______________________________________________ Perldl mailing list [email protected] http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
