Performance regression in DataFrame reduction ops
The `stat_ops.FrameOps` are generally showing a slowdown since a few days, see eg https://pandas.pydata.org/speed/pandas/#stat_ops.FrameOps.time_op?python=3.8&Cython=0.29.21&p-op='mean'&p-dtype='int'&p-axis=0&commits=8dbb593d-7043f8fa

The indicated range is https://github.com/pandas-dev/pandas/compare/8dbb593d...7043f8fa, but don't directly see which commit might be the cause cc @jbrockmendel 