Fix Net monitor for large uptimes/bytecounts

My laptop currently has rx/tx bytes in 10s of gigabytes and it's only
been up for 20 days. Normally it's several times more. At this point,
Float can only tell the difference of 4KB and up:

Prelude> let x = (50 * 2^30 :: Float) in (x + 2000) - x
0.0
Prelude> let x = (50 * 2^30 :: Float) in (x + 3000) - x
4096.0

This commit makes the Net monitor read Word64 which is exactly what the
kernel prints into /proc/net/dev [1] and converts to Float only after
subtracting the two numbers.

[1] https://github.com/torvalds/linux/blob/7a308bb3016f57e5be11a677d15b821536419d36/net/core/net-procfs.c#L82

Still, I think it's time to switch from Float to Double. At half-gigabit
speeds (easily attainable at home while rsyncing over a direct UTP cable
between two post-2010 laptops), Float can only tell the difference of
8 bytes and up (and I'm not even considering takeDigits!). That's
probably okay for a Net monitor in xmobar, but we're so close to the
limit it makes sense to move to Double just in case.

0 files changed, 0 insertions, 0 deletions