tcp_output starving -- is due to mbuf get delay?

David Gilbert dgilbert at
Wed Apr 9 21:15:28 PDT 2003

>>>>> "Jin" == Jin Guojun <[DSD]" <j_guojun at>> writes:

Jin> Some details was left behind -- The machine is 2 GHz Intel P4
Jin> with 1 GB memory, so the delay is not from either CPU or lack of
Jin> memory.

I just want to quickly jump in with the comment that our GigE tests of
routing through FreeBSD have exposed several-order-of-magnitude
differences by changing ram/motherboard/which-slot-the-card-is-in.

Do not assume that a fast CPU is the key.  We went through 10
motherboards to commission the current routers ... and sometimes
faster cpus would route slower (in various combinations of
motherboards and RAM).


|David Gilbert, Velocet Communications.       | Two things can only be     |
|Mail:       dgilbert at             |  equal if and only if they |
|                              |   are precisely opposite.  |

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