CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2015/08/14 01:24:18
Modified files:
sys/dev/pci : if_myx.c
Log message:
rework how we track the packets on the rx rings.
originally there were two mutex protected lists for rx packets, a
list of free packets, and a list of packets that were on the ring.
filling the ring popped packets off the free list, attached an mbuf
and dmamapped it, and pushed it onto the list of active packets.
the hw fills packets in order, so on rx completion we'd pop packets
the active list, unmap the mbuf and shove it up the stack before
putting the packet on the free list.
the problem with the lists is that every rx ring operation resulted
in two mutex ops. so 4 mutex ops per packet after you do both fill
and rxeof.
this replaces the mutexed lists with rings that shadow the hardware
rings. filling the rx ring pushes a producer index along, while
rxeof chases it with a consumer. because we know only one thing can
do either of those tasks at a time, we can get away with not using
atomic ops for them.
there's more to be done, but this is a good first step.
