http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43706
--- Comment #23 from Alexander Peslyak <solar-gcc at openwall dot com> 2010-11-09 16:32:53 UTC --- (In reply to comment #20) > Maybe we could agree on a compromise for a start. Alexander, what are the > corresponding results for GOMP_SPINCOUNT=100000? I reproduced slowdown of 5% to 35% (on different pieces of code) on an otherwise-idle dual-E5520 system (16 logical CPUs) when going from gcc 4.5.0's defaults to GOMP_SPINCOUNT=10000. On all but one test, the original full speed is restored with GOMP_SPINCOUNT=100000. On the remaining test, the threshold appears to be between 100000 (still 35% slower than full speed) and 200000 (original full speed). So if we're not going to have a code fix soon enough maybe the new default should be slightly higher than 200000. It won't help as much as 10000 would for cases where this is needed, but it would be of some help.
