net: socionext: remove mmio reads on Tx
authorIlias Apalodimas <ilias.apalodimas@linaro.org>
Fri, 14 Dec 2018 08:59:01 +0000 (10:59 +0200)
committerDavid S. Miller <davem@davemloft.net>
Sat, 15 Dec 2018 21:15:19 +0000 (13:15 -0800)
commit35e07d23473972b8876f98bcfc631ebcf779e870
tree0e3b73f6f2df1cf7d29c70641151de883b1246fc
parent17a12eaaf09a2fa3ea6997e3b5be8bc05fc60ee4
net: socionext: remove mmio reads on Tx

Currently the driver issues 2 mmio reads to figure out the number of
transmitted packets and clean them. We can get rid of the expensive
reads since BIT 31 of the Tx descriptor can be used for that.
We can also remove the budget counting of Tx completions since all of
the descriptors are not deliberately processed.

Performance numbers using pktgen are:
size  pre-patch(pps)  post-patch(pps)
64       362483           427916
128      358315           411686
256      352725           389683
512      215675           216464
1024     113812           114442

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/socionext/netsec.c