Hi,

I've been following armv7 recent changes and these days I was able to
compare kernel compile times on 2 of the supported boards.

The first is an omap BeagleBone Black with a NFS-mounted /usr/src. It's
pretty stable and I had no issues so far with what is supported.

The second is a sunxi CubieBoard 2 with the Allwinner A20 SoC. This one
has a 1.8" hdd instead.

BeagleBone Black:
(...)
ld -T ldscript --warn-common -nopie -S -o bsd ${SYSTEM_HEAD} vers.o ${OBJS}
text    data    bss     dec     hex
3684900 104816  470508  4260224 410180
   59m00.17s real    51m31.67s user     3m43.93s system

CubieBoard 2:
(...)
ld -T ldscript --warn-common -nopie -S -o bsd ${SYSTEM_HEAD} vers.o ${OBJS}
text    data    bss     dec     hex
3684128 104816  470080  4259024 40fcd0
  269m38.01s real   252m33.07s user    12m29.56s system

The sizes are slightly different because one source tree is maybe a
dozen commits ahead of the other, so no significant changes.

The cb2 host kernel has a small workaround published by Patrick Wildt on
bugs@, to only flush a TLB for a specified VA, not the entire TLB. It
prevents a flood of pmap_fault_fixup messages on console. I know there
are things to be done here, although I don't know if the slow cb2 times
compared to bbb are related to this.

http://marc.info/?l=openbsd-bugs&m=145840460330909&w=2

I was expecting cb2 to be faster than bbb.

Related to sxie(4) on cb2, it's common to lose the ssh session with
packet_write_poll when there is no activity. I was able to compile the
full kernel without problem, though.

packet_write_poll: Connection to 192.168.1.220 port 22: Host is down

It seems the imx are much more popular on arm@ because they are faster,
but these boards are tough to find in Brazil.

Just a little feedback.

-- 
db

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