Re: [E1000-devel] [PATCH 01/21] net: slight optimization of addr compare for some modules

Ding Tianhong
2013-12-24T01:45:05Z

On 2013/12/24 1:20, Alexander Duyck wrote:
> On 12/22/2013 09:09 PM, Ding Tianhong wrote:
>> Use the recently added and possibly more efficient
>> ether_addr_equal_unaligned to instead of memcmp.
>>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> Cc: netdev@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Cc: e1000-devel@lists.sourceforge.net
>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
>> ---
>> drivers/net/bonding/bond_3ad.c | 2 +-
>> drivers/net/ethernet/3com/3c509.c | 3 +--
>> drivers/net/ethernet/broadcom/bnx2x/bnx2x_sp.c | 10 ++++------
>> drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c | 2 +-
>> drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c | 2 +-
>> drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c | 2 +-
>> drivers/net/ethernet/chelsio/cxgb3/l2t.c | 2 +-
>> drivers/net/ethernet/cisco/enic/enic_pp.c | 2 +-
>> drivers/net/ethernet/emulex/benet/be_main.c | 2 +-
>> drivers/net/ethernet/intel/igbvf/netdev.c | 2 +-
>> drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c | 3 +--
>> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 4 ++--
>> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 2 +-
>> drivers/net/ethernet/micrel/ksz884x.c | 9 ++++-----
>> drivers/net/ethernet/neterion/vxge/vxge-main.c | 2 +-
>> drivers/net/ethernet/packetengines/yellowfin.c | 8 ++------
>> drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c | 2 +-
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_hw.c | 4 ++--
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_io.c | 4 ++--
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c | 4 ++--
>> drivers/net/ethernet/renesas/sh_eth.c | 2 +-
>> drivers/net/ethernet/seeq/sgiseeq.c | 2 +-
>> drivers/net/ethernet/sun/sunvnet.c | 2 +-
>> drivers/net/ethernet/ti/cpsw_ale.c | 2 +-
>> drivers/net/fddi/skfp/fplustm.c | 3 ++-
>> drivers/net/plip/plip.c | 2 +-
>> net/caif/cfrfml.c | 2 +-
>> 27 files changed, 39 insertions(+), 47 deletions(-)
>
> What is it you are trying to optimize for, size or speed? Most of these
> calls are in slow path. Replacing the memcmp with an inline operation
> may provide little to no gain in terms of speed and in many cases as you
> might actually be increasing the resultant driver size.
>
> Also I would recommend reviewing the addresses you are comparing. It is
> likely that you could use ether_addr_equal or compare_ether_addr in many
> cases as I suspect a number of spots are using 16b aligned MAC addresses
> for both operands.
>
> Thanks,
>
> Alex
>
> .

Yes, as the title said, slight optimization, and I think there will be no
negative effect for these places. The patchset still have many problem,
many places should use the ether_addr_equal as you said, I will fix it later.
Thank you for reviewing the patch.

Regards
Ding

>