carbon: reduce SYNC_EVERY_N after doing pypy benchmarks
carbon: reduce SYNC_EVERY_N after doing pypy benchmarks

criteo/biggraphite,iksaif/biggraphite,iksaif/biggraphite,iksaif/biggraphite,Thib17/biggraphite,criteo/biggraphite,Thib17/biggraphite,dpanth3r/biggraphite,criteo/biggraphite,Thib17/biggraphite,iksaif/biggraphite,criteo/biggraphite,Thib17/biggraphite