Speaker
Alessandro Lonardo
(ROMA1)
Description
While GPGPU paradigm is widely recognized as an effective approach to
high performance computing, its usage in low-latency, real-time
systems is still in early stages in HEP experiments.
GPUs typically show deterministic behaviour in terms of processing
latency once data are available in their internal memories, but
assessment of real-time features of a standard GPGPU system takes a
careful characterization of all subsystems along data stream path.
The networking subsystem results the most critical one in terms of
latency fluctuations.
Our envisioned solution to this issue is NaNet, an FPGA-based PCIe
Network Interface Card (NIC) design featuring a configurable set of
network channels with direct access to NVIDIA Fermi/Kepler GPU
memories (GPUDirect).
NaNet design currently supports both standard - 1GbE (1000Base-T) and
10GbE (10Base-R) - and custom - 34Gbps APElink and 2.5Gbps
deterministic latency KM3link - channels, but its modularity allows
for a straightforward inclusion of other link technologies.
To avoid host OS intervention on data stream and remove a possible
source of jitter, the design includes a transport layer offload module
with cycle-accurate upper-bound latency, supporting UDP, KM3link Time
Domain Multiplexing and APElink protocols.
After NaNet architecture description and its latency/bandwidth
characterization for all supported links, two real world use cases
will be presented: the GPU-based low level trigger for the RICH
detector in NA62 experiment and the on-/off-shore data link for KM3
underwater neutrino telescope.
NaNet performances in both experiments will be presented and discussed.
Primary authors
Alessandro Lonardo
(ROMA1)
Andrea Biagioni
(ROMA1)
Elena Pastorelli
(INFN)
Fabrizio Ameli
(ROMA1)
Dr
Francesca Locicero
(INFN)
Francesco Simeone
(ROMA1)
Francesco Simula
(ROMA1)
Gianluca Lamanna
(PI)
Laura Tosoratto
(ROMA1)
Dr
Luca Pontisso
(Università di Roma "Sapienza")
Marco Sozzi
(PI)
Dr
Ottorino Frezza
(INFN)
Piero Vicini
(ROMA1)
Roberto Ammendola
(ROMA2)
