CONFIG_IOSCHED_* in m68k kernel
Hello,
I have observed that the m68k kernels available from [1] seem to have all the
I/O Schedulers selected. In other words all CONFIG_IOSCHED are being built
in to the kernel (at least in the 2.6.26 and 2.6.28 available for the Amiga
that I checked). For example:
#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
# CONFIG_DEFAULT_AS is not set
# CONFIG_DEFAULT_DEADLINE is not set
CONFIG_DEFAULT_CFQ=y
# CONFIG_DEFAULT_NOOP is not set
CONFIG_DEFAULT_IOSCHED="cfq"
I have done some checking, and have found that:
a) CONFIG_IOSCHED_NOOP uses the least amount of RAM.
b) CONFIG_IOSCHED_DEADLINE is the next
c) CONFIG_IOSCHED_AS and CONFIG_IOSCHED_CFQ are about the same and
more than NOOP or DEADLINE.
d) The kernel default for m68k is CONFIG_DEFAULT_AS=y (per 2.6.29.1).
Is there a reason why all three are being built in to the m68k installer kernels?
After some checking [2, among others] and testing, I would suggest the following:
#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
# CONFIG_IOSCHED_AS is not set
# CONFIG_IOSCHED_DEADLINE is not set
# CONFIG_IOSCHED_CFQ is not set
# CONFIG_DEFAULT_AS is not set
# CONFIG_DEFAULT_DEADLINE is not set
# CONFIG_DEFAULT_CFQ is not set
CONFIG_DEFAULT_NOOP=y
CONFIG_DEFAULT_IOSCHED="noop"
As this configuration minimizes kernel footprint, the various other schedulers
can be made modules with no change in the footprint, but is there value in
having them in the initrd for the installler?
Thoughts?
--Lance
[1] http://people.debian.org/~smarenka/m68k/kernel/
[2] http://www.wlug.org.nz/LinuxIoScheduler
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