Gigabit ethernet very slow.

Matthew D. Fuller fullermd at
Mon Jun 26 21:26:19 UTC 2006

On Mon, Jun 26, 2006 at 05:05:26PM +1000 I heard the voice of
Michael Vince, and lo! it spake thus:
> According to pftop (with modulate state rules) I am able to get
> about 85megs/sec when I don't have dd running. dd does indeed eats a
> fair amount of cpu (40%) on the AMD64 6-stable machine.

dd does ridiculously small (512 byte?) read/writes, so it's gotta do a
LOT of system calls and a lot of context switching when you don't give
it a bigger blocksize.

Matthew Fuller     (MF4839)   |  fullermd at
Systems/Network Administrator |
           On the Internet, nobody can hear you scream.

More information about the freebsd-performance mailing list