patrick at myri.com
Fri Feb 6 04:17:43 EST 2004
Ah Mark, I could not resist. Actually I could, but the list has been a
little boring lately, so... :-)
Mark Hahn wrote:
> (Myri seems not to be very ambitious, and 10G eth seems to be straying into
> a morass of tcp-offload and the like...)
Myri is very ambitious, but you can be carefully ambitious or
marketingly ambitious. Nobody buys an interconnect looking only at the
specs. People try, benchmark, run their code, rationalize and buy what
they need at the right price. If you look at what people are doing,
there is a lot of Ethernet (Fast and GigE) because thats good enough for
many, many codes. Then there is a smaller market for more demanding
needs, either in term of performance or scalability, where you want to
find the sweet spot in the performance/price curve.
Does it make sense to have 10Gb now ? I don't think so, and for several
* PCI-Express is not here yet: It's coming, yes, but it's not available
in volume. Today, PCI-X supports 1 GB bidirectional, which is 4 Gb link
speed. It's clearly the bottleneck right now. HyperTransport looks
attractive, but there is no connector defined yet and vendors should be
able to see a potential for volume before to commit resources for a
native HT interface.
* 10 Gb optics are still expensive: price is going down, but there is
not enough volume yet to drive the price down faster. Copper ? I still
have nightmares about copper. 10 GigE will drive the technology price
down as the 10 GigE market blossoms.
* 10 GigE is not attractive enough yet because there is no clear
improvement at the application level. Running a naive IP stack at 10 Gb
requires a lot of resources on the host. RDMA is just a buzword, it's
not The Solution. Storage may leverage RDMA, but not IP and certainly
not MPI. That's why people are working to put processing on the data
path, but it is far from obvious so it takes some time.
Gigabit is the clear winner today and 10 GigE will be the clear winner
tomorrow, because Ethernet is the de facto Standard. Everybody else are
parasites, either breading on niches or marketing poop...
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