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Postings from January 2001
On Tue, Jan 23, 2001 at 01:02:42PM +0000, Nick Ing-Simmons wrote: > Nicholas Clark <nick@ccl4.org> writes: > >If one uses Duff's device in PERL_HASH, the regression tests go about 2% > >faster. > >Without: > > > >All tests successful. > >u=1.33 s=0.46 cu=62.27 cs=10.54 scripts=273 tests=21120 > > > >real 2m16.388s > >user 1m3.610s > >sys 0m11.000s > > > >With: > > > >All tests successful. > >u=1.4 s=0.32 cu=59.86 cs=10.71 scripts=273 tests=21120 > > > >real 2m11.748s > >user 1m1.260s > >sys 0m11.030s > > > > > >perl gets about .25% bigger: > > > >-rwxrwxr-x 1 nick 1001 785667 Jan 20 15:36 bleadperl/perl > >-rwxrwxr-x 1 nick 1001 787683 Jan 23 11:51 bleadperl-duff/perl > Would be interesting to see what inline costs in speed/size. > Can you experiment with putting the "snazzy" hash in a _real_ function > (in pp_hot.c or perhaps hv.c) and making PERL_HASH call that? The 1 at a time loop in a function Perl_hash at the end of pp_hot.c: All tests successful. u=1.54 s=0.37 cu=63.85 cs=10.94 scripts=273 tests=21120 real 2m13.488s user 1m5.390s sys 0m11.310s The 8 fold Duff's device in that function: All tests successful. u=1.33 s=0.4 cu=62.43 cs=10.69 scripts=273 tests=21120 real 2m8.974s user 1m3.760s sys 0m11.090s I delete the previous binary before I thought to measure the size, but the 8 fold is: -rwxrwxr-x 1 nick 1001 785501 Jan 23 15:50 perl Hmm. Calling an optimised hash function is about as fast as in-lining a simple one. Nicholas ClarkThread Previous | Thread Next