Recent versions of Linux (version 2.6.17 and later) have full autotuning with 4 MB maximum buffer sizes. Except in some rare cases, manual tuning is unlikely to substantially improve the performance of these kernels over most network paths, and is not generally recommended
Since autotuning and large default buffer sizes were released progressively over a succession of different kernel versions, it is best to inspect and only adjust the tuning as needed. When you upgrade kernels, you may want to consider removing any local tuning.
