Low latency FPGA options

[Jordan Fix]

Hello,

I am looking to use FPGA's as specialized coprocessors to increase
performance on different applications. I would like the lowest latency
possible to memory. I have only found options with PCIE and
HyperTransport, but I was hoping to find something similar to this
which I assume would have lower latency than PCIE or HyperTransport:
( http://www.nallatech.com/intel-xeon-fsb-fpga-socket-fillers.html ).
However it seems that product is no longer in production.

Are there any similar products to the above link? I suppose a related
question is, how much lower latency would there be for an FPGA on the
FSB instead of PCIE or HyperTransport?

Thanks,
Jordan

 

[John Adair]

Jordan

There were 2 or 3 companies manufacturing accelerators that were aimed
at sitting in a second processor socket. For companies that have used
this technique the problems of keeping up with socket changes was
always going to be a problem. The other problem is that the second
socket on most motherboards, and maybe all, has dissappeared. Main
reason for that is multi-core processors that don't need 2+ sockets.

PCIe latency can be a big factor if you doing a HPC system that only
does "small" commands, instructions or functions because the PCIe
latency costs you much more than you gain. "Big" commands,
instructions, or functions are usually ok. Chained systems or systems
where the processor is only a manager usually work well. That's why in
our HPC systems, using our Merrick and Broaddown family boards, we
make features like 1G and 10G Ethernet directly available to these
boards that cuts out the PCIe structure.Similarly we now do real world
sensor interfacing for these systems through our Lamachan2 board so
there is minimal latency.

There are usually other ways to tackle most problems but it depends on
what you need to achieve. Here we do a lot of different things
depending on a customer system requirements and rarely is the same
approach used for any 2 customers.

John Adair
Enterpoint Ltd. - Home of FPGA HPC systems.

On Apr 1, 7:14 am, Jordan Fix <jfi...@gmail.com> wrote:

Hello,

I am looking to use FPGA's as specialized coprocessors to increase
performance on different applications. I would like the lowest latency
possible to memory. I have only found options with PCIE and
HyperTransport, but I was hoping to find something similar to this
which I assume would have lower latency than PCIE or HyperTransport:
(http://www.nallatech.com/intel-xeon-fsb-fpga-socket-fillers.html).
However it seems that product is no longer in production.

Are there any similar products to the above link? I suppose a related
question is, how much lower latency would there be for an FPGA on the
FSB instead of PCIE or HyperTransport?

Thanks,
Jordan

 

[Michael S]

On Apr 1, 9:14 am, Jordan Fix <jfi...@gmail.com> wrote:

Hello,

I am looking to use FPGA's as specialized coprocessors to increase
performance on different applications. I would like the lowest latency
possible to memory. I have only found options with PCIE and
HyperTransport, but I was hoping to find something similar to this
which I assume would have lower latency than PCIE or HyperTransport:
(http://www.nallatech.com/intel-xeon-fsb-fpga-socket-fillers.html).
However it seems that product is no longer in production.

Are there any similar products to the above link? I suppose a related
question is, how much lower latency would there be for an FPGA on the
FSB instead of PCIE or HyperTransport?

Thanks,
Jordan

Intel AGTL+ FSB is dead and buried. Also, I am not sure that even when
it was alive the latency was really lower than HyperTransport.
AMD HTX slots also close to non-existent.
Intel QPI made short appearance in the desktops but was quickly killed
by more integrated solutions and, by now, exists only in servers.
Besides, QPI is not very narrow source synchronous parallel bus that,
in its latest incarnation, runs at 6.4-8.0 GT/s. I.e. even the most
modern FPGA will have very hard time talking to it

Overall, low latency off-chip co-processors look like technological
dead end. Sorry.
You better start looking for a way to live with relatively high
latency of PCIe interface.

 

[glen herrmannsfeldt]

Jordan Fix <jfix71@gmail.com> wrote:

I am looking to use FPGA's as specialized coprocessors to increase
performance on different applications. I would like the lowest latency
possible to memory.

Sometimes you can't live without low latency, but reasonably
often you can do it pipelined. That might mean doing two or three
of whatever you are doing instead of one, using separate data
streams.

-- glen