Why is MySQL nearly twice as fast on Linux/AMD64 Vs.FreeBSD/AMD64?

[Andrew Gallatin]

Steven Hartland writes:
 > Ok its IO (netcard drivers).
 > TBH after looking at this benchmarker I'd say its pretty useless
 > its testing packet throughput / rpc time not the database.
 > 
 > Typical db load is not all insert statements its not even mostly
 > insert statements its selects. Saying that there's some startling results
 > below.
 > Exec summary:
 > FreeBSD 5.1.2 (i386)
 > local: 22834.872368421 records per second
 > fxp 100Mb: 3854.06863517 records per second
 > bge 100Mb: 2501.66999862 records per second
 > bge 1Gb: 3281.65229885 records per second

Nice work.  Does this translate pretty much directly into netperf
request/response results? (netperf -tTCP_RR -Hremote)

Assuming it does, have you tried "tuning" the bge interrupt coalescing
params?  Without adding an interface, I'd just suggest doing something
like changing sc->bge_rx_max_coal_bds from 64 to 1 around like 2350 of
dev/bge/if_bge.c, rebuilding the driver, and seeing what changes.  I'm
betting that will turn off recv interrupt coalescing and reduce your
latency some.

Drew