------- Comment #2 from hubicka at gcc dot gnu dot org 2005-10-28 16:32 -------
I've benchmarked the change reducing maximum number of iterations predicted for
loop with constant bounds to 100 and 10 respectively. 100 makes no actual
change to x86-64 SPEC run, 10 seems to result in small degradation:
164.gzip 1400 117 1193* 1400 117 1195*
175.vpr 1400 166 845* 1400 166 844*
176.gcc 1100 107 1031* 1100 106 1035*
181.mcf 1800 335 537* 1800 333 541*
186.crafty 1000 49.8 2010* 1000 49.7 2012*
197.parser 1800 232 777* 1800 230 783*
252.eon 1300 71.3 1823* 1300 75.4 1724*
253.perlbmk 1800 125 1440* 1800 124 1446*
254.gap 1100 95.3 1154* 1100 96.0 1146*
255.vortex 1900 112 1689* 1900 113 1689*
256.bzip2 1500 149 1005* 1500 149 1005*
300.twolf 3000 353 850* 3000 353 851*
Est. SPECint_base2000 1118
Est. SPECint2000 1114
(specFP still in progress). I will also try the idea of increasing estimated
number of iterations for loops without contatn bounds when some high limit is
known for loop with constant bound within function, but actually I don't like
that idea much anymore as it would result in profile to be artifically steep on
wrong places, most probably :(
Does the missprediction manifest somehow on PPC?
--
hubicka at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |hubicka at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2005-10-23 20:11:24 |2005-10-28 16:32:22
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24487
