[Ltop] gcc (and clang) vector extensions...

Can’t resist sharing this one ;-)

With a fairly small code change (see https://svnweb.cern.ch/trac/lhcb/changeset/175997) which does some explicit vectorisation using the gcc vector extension, I’ve been able to get the overall HLT to run 3% faster (according to valgrind). Not bad for 2 days of work ;-) (now, if only I could get 3% of the investment money in the event filter farm payed out to me, I could go on vacation for the remainder of the year)

— Gerhard