e1000e: slow performance between two 82579 connected via 10Mbit hub
Two 82579 LOMs connected via a 10Mb hub experience extraordinarily low performance. This is because 82579 is excessively aggressive on transmit at 10Mb half-duplex and will not provide sufficient time for the link partner to transmit. When the link partner is also 82579, the result is a lot of collisions (and corresponding re-transmits) that cause the poor performance. To work-around this issue, significantly increase the IPG in the MAC to allow enough gap for the link partner to transmit and reduce the Rx latency in the analog PHY to 0 to reduce the number of collisions. Signed-off-by:Bruce Allan <bruce.w.allan@intel.com> Tested-by:
Jeff Pieper <jeffrey.e.pieper@intel.com> Signed-off-by:
Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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