[Beowulf] Re: typical latencies for gigabit ethernet
gerry.creager at tamu.edu
Mon Jun 29 06:55:56 PDT 2009
Dave Love wrote:
> Gerry Creager <gerry.creager at tamu.edu> writes:
>> Can you say something about any tuning you did to get decent results?
> To get the lowest latency, turn off rx interrupt coalescence, either
> with ethtool or module parameters, depending on the driver. Of course,
> you may not want to turn it off completely, depending on how much load
> the extra interrupts cause.
I'll look at that and give it a try. Thanks.
>> We've had some interesting problems (until lately; new broadcom drivers
>> helped) getting decent performance. We're using Dell 1950's with
>> Harpertown and broadcom NICs are native.
>> Which driver parms had to get tweaked?
> There are (at least) two different drivers for Broadcoms, and I've no
> idea what that hardware has. I've only used tg3, and am actually
> somewhat confused by it. (I haven't had time to try to understand the
> driver code and I'm not primarily interested in those NICs as the
> nVidias on our boxes seem better.) Are you using tg3 or bnx2?
I had rather nasty results with tg3 and abandoned it. We're using bnx2
now. The latest iteration seems (guardedly) better than the last one.
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
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