Search results for "infiniband"

Hits ?▲	Authors	Title	Venue	Year	Link	Author keywords
17	Tejus Gangadharappa, Matthew J. Koop, Dhabaleswar K. Panda 0001	Designing and Evaluating MPI-2 Dynamic Process Management Support for InfiniBand.	ICPP Workshops	2009	DBLP DOI BibTeX RDF
17	Diego Lugones, Daniel Franco 0002, Emilio Luque	Adaptive Multipath Routing for Congestion Control in InfiniBand Networks.	ICPP Workshops	2009	DBLP DOI BibTeX RDF
17	Ping Lai, Hari Subramoni, Sundeep Narravula, Amith R. Mamidala, Dhabaleswar K. Panda 0001	Designing Efficient FTP Mechanisms for High Performance Data-Transfer over InfiniBand.	ICPP	2009	DBLP DOI BibTeX RDF
17	José Miguel Montañana Aliaga, Michihiro Koibuchi, Takafumi Watanabe, Tomoyuki Hiroyasu, Hiroki Matsutani, Hideharu Amano	An On/Off Link Activation Method for Power Regulation in InfiniBand.	PDPTA	2009	DBLP BibTeX RDF
17	Adit Ranadive, Ada Gavrilovska, Karsten Schwan	IBMon: monitoring VMM-bypass capable InfiniBand devices using memory introspection.	HPCVirt@EuroSys	2009	DBLP DOI BibTeX RDF
17	Hari Subramoni, Matthew J. Koop, Dhabaleswar K. Panda 0001	Designing Next Generation Clusters: Evaluation of InfiniBand DDR/QDR on Intel Computing Platforms.	Hot Interconnects	2009	DBLP DOI BibTeX RDF
17	Dhabaleswar K. Panda 0001, Matthew J. Koop, Pavan Balaji	Tutorial: Designing High-End Computing Systems with Infiniband and 10-Gigabit Ethernet.	Hot Interconnects	2009	DBLP DOI BibTeX RDF
17	Torsten Hoefler, Timo Schneider, Andrew Lumsdaine	Optimized Routing for Large-Scale InfiniBand Networks.	Hot Interconnects	2009	DBLP DOI BibTeX RDF
17	Dhabaleswar K. Panda 0001, Matthew J. Koop, Pavan Balaji	Tutorial: Infiniband and 10-Gigabit Ethernet for Dummies.	Hot Interconnects	2009	DBLP DOI BibTeX RDF
17	Gopalakrishnan Santhanaraman, Tejus Gangadharappa, Sundeep Narravula, Amith R. Mamidala, Dhabaleswar K. Panda 0001	Design alternatives for implementing fence synchronization in MPI-2 one-sided communication for InfiniBand clusters.	CLUSTER	2009	DBLP DOI BibTeX RDF
17	Benjamin A. Allan, Helen Chen, Scott Cranford, Ron Minnich, Don W. Rudish, Lee Ward	On optimizing I/O through InfiniBand RDMA for commodity clusters.	CLUSTER	2009	DBLP DOI BibTeX RDF
17	Abhinav Vishnu, Manojkumar Krishnan, Dhabaleswar K. Panda 0001	An efficient hardware-software approach to network fault tolerance with InfiniBand.	CLUSTER	2009	DBLP DOI BibTeX RDF
17	Darren J. Kerbyson, Michael Lang 0003, Greg Johnson	Infiniband Routing Table Optimizations for Scientific Applications.	Parallel Process. Lett.	2008	DBLP DOI BibTeX RDF
17	Ryan E. Grant, Mohammad J. Rashti, Ahmad Afsahi	An Analysis of QoS Provisioning for Sockets Direct Protocol vs. IPoIB over Modern InfiniBand Networks.	ICPP Workshops	2008	DBLP DOI BibTeX RDF
17	Weikuan Yu, Nageswara S. V. Rao, Jeffrey S. Vetter	Experimental Analysis of InfiniBand Transport Services on WAN.	NAS	2008	DBLP DOI BibTeX RDF
17	Wan Huang, Jizhong Han, Jin He, Lisheng Zhang, Yao Lin	Enabling RDMA Capability of InfiniBand Network for Java Applications.	NAS	2008	DBLP DOI BibTeX RDF
17	Ranjit Noronha, Dhabaleswar K. Panda 0001	IMCa: A High Performance Caching Front-End for GlusterFS on InfiniBand.	ICPP	2008	DBLP DOI BibTeX RDF
17	Ouissem Ben Fredj, Éric Renault	RWAPI over InfiniBand: Design and Performance.	Scalable Comput. Pract. Exp.	2007	DBLP BibTeX RDF
17	Galen M. Shipman, Ron Brightwell, Brian Barrett, Jeffrey M. Squyres, Gil Bloch	Investigations on InfiniBand: Efficient Network Buffer Utilization at Scale.	PVM/MPI	2007	DBLP DOI BibTeX RDF
17	Qi Gao 0004, Wei Huang 0003, Matthew J. Koop, Dhabaleswar K. Panda 0001	Group-based Coordinated Checkpointing for MPI: A Case Study on InfiniBand.	ICPP	2007	DBLP DOI BibTeX RDF
17	Omar Aldaoud, Houssain Kettani, Krishnapriya Guduru, Qutaibah M. Malluhi	Storage Performance over Fast Ethernet, Giga Ethernet, Giga Ethernet TOE and InfiniBand.	PDPTA	2007	DBLP BibTeX RDF
17	Sayantan Sur, Matthew J. Koop, Lei Chai, Dhabaleswar K. Panda 0001	Performance Analysis and Evaluation of Mellanox ConnectX InfiniBand Architecture with Multi-Core Platforms.	Hot Interconnects	2007	DBLP DOI BibTeX RDF
17	Sven-Arne Reinemo, Tor Skeie, Thomas Sødring, Olav Lysne, O. Trudbakken	An overview of QoS capabilities in infiniband, advanced switching interconnect, and ethernet.	IEEE Commun. Mag.	2006	DBLP DOI BibTeX RDF
17	Shihang Yan, Geyong Min, Irfan Awan	Performance Analysis of Credit-Based Flow Control in InfiniBand Interconnection Networks.	J. Interconnect. Networks	2006	DBLP DOI BibTeX RDF
17	Vivek Kashyap	Dynamic Host Configuration Protocol (DHCP) over InfiniBand.	RFC	2006	DBLP DOI BibTeX RDF
17	Vivek Kashyap	IP over InfiniBand (IPoIB) Architecture.	RFC	2006	DBLP DOI BibTeX RDF
17	Jerry Chu, Vivek Kashyap	Transmission of IP over InfiniBand (IPoIB).	RFC	2006	DBLP DOI BibTeX RDF
17	Vivek Kashyap	IP over InfiniBand: Connected Mode.	RFC	2006	DBLP DOI BibTeX RDF
17	Amith R. Mamidala, Abhinav Vishnu, Dhabaleswar K. Panda 0001	Efficient Shared Memory and RDMA Based Design for MPI_Allgather over InfiniBand.	PVM/MPI	2006	DBLP DOI BibTeX RDF	MPI_Allgather, MPI, Shared Memory, RDMA
17	Hubert Eichner, Carsten Trinitis, Tobias Klug	Software Shared Memory Communications with InfiniBand.	ARCS Workshops	2006	DBLP BibTeX RDF
17	Yonghao Zhou, Jizhong Han, Jin He, Hongwei Zhang, Zifeng Xiao	SADLBoIB: Self-Adaptive Dynamic Load Balance over InfiniBand.	FCST	2006	DBLP DOI BibTeX RDF
17	Torsten Hoefler, Carsten Viertel, Torsten Mehlan, Frank Mietke, Wolfgang Rehm	Assessing Single-Message and Multi-Node Communication Performance of InfiniBand.	PARELEC	2006	DBLP DOI BibTeX RDF
17	Omar Aldaoud, Houssain Kettani, Krishnapriya Guduru, Qutaibah M. Malluhi	Performance Analysis of Network Storage Manager System Using DAFS over InfiniBand.	PDPTA	2006	DBLP BibTeX RDF
17	Matthew J. Koop, Wei Huang 0003, Abhinav Vishnu, Dhabaleswar K. Panda 0001	Memory Scalability Evaluation of the Next-Generation Intel Bensley Platform with InfiniBand.	Hot Interconnects	2006	DBLP DOI BibTeX RDF
17	Gopalakrishnan Santhanaraman, Jiesheng Wu, Wei Huang 0003, Dhabaleswar K. Panda 0001	Designing Zero-Copy Message Passing Interface Derived Datatype Communication Over Infiniband: Alternative Approaches and Performance Evaluation.	Int. J. High Perform. Comput. Appl.	2005	DBLP DOI BibTeX RDF
17	Inho Park, Seon Wook Kim	The distributed virtual shared-memory system based on the InfiniBand architecture.	J. Parallel Distributed Comput.	2005	DBLP DOI BibTeX RDF
17	Inho Park, Seon Wook Kim	Study of OpenMP applications on the InfiniBand-based software distributed shared-memory system.	Parallel Comput.	2005	DBLP DOI BibTeX RDF
17	Hsien-Ting Kuo, Jiazheng Zhou, Xuan-Yi Lin, Yeh-Ching Chung	An Efficient and Low Overhead Random Forwarding Table Construction Method for Deadlock-Free Routing Algorithms in Infiniband Networks.	IASTED PDCS	2005	DBLP BibTeX RDF
17	Jie Tao 0001, Wolfgang Karl, Carsten Trinitis	Implementing an OpenMP Execution Environment on InfiniBand Clusters.	IWOMP	2005	DBLP DOI BibTeX RDF
17	Pavan Balaji, Sundeep Narravula, Karthikeyan Vaidyanathan, Hyun-Wook Jin, Dhabaleswar K. Panda 0001	On the provision of prioritization and soft qos in dynamically reconfigurable shared data-centers over infiniband.	ISPASS	2005	DBLP DOI BibTeX RDF
17	Lei Chai, Sayantan Sur, Hyun-Wook Jin, Dhabaleswar K. Panda 0001	Analysis of Design Considerations for Optimizing Multi-Channel MPI over InfiniBand.	IPDPS	2005	DBLP DOI BibTeX RDF
17	Wei Huang 0003, Gopalakrishnan Santhanaraman, Hyun-Wook Jin, Dhabaleswar K. Panda 0001	Scheduling of MPI-2 One Sided Operations over InfiniBand.	IPDPS	2005	DBLP DOI BibTeX RDF
17	Dennis Dalessandro, Pete Wyckoff	Fast Scalable File Distribution Over Infiniband.	IPDPS	2005	DBLP DOI BibTeX RDF
17	José Miguel Montañana, José Flich, Antonio Robles, José Duato	A Scalable Methodology for Computing Fault-Free Paths in InfiniBand Torus Networks.	ISHPC	2005	DBLP DOI BibTeX RDF
17	Ariel Cohen 0003	A performance analysis of the sockets direct protocol (SDP) with asynchronous I/O over 4X InfiniBand.	IPCCC	2004	DBLP DOI BibTeX RDF
17	Inho Park, Hong-Wook Choi, Youngsun Han, Seokjoong Hwang, Seon Wook Kim, Kyung Park	Implementation of the Software Distributed Shared-Memory System on the InfiniBand.	PDPTA	2004	DBLP BibTeX RDF
17	Jiuxing Liu, Amith R. Mamidala, Abhinav Vishnu, Dhabaleswar K. Panda 0001	Performance evaluation of InfiniBand with PCI Express.	Hot Interconnects	2004	DBLP DOI BibTeX RDF
17	Dhabaleswar K. Panda 0001	State of InfiniBand in designing HPC clusters, storage/file systems, and datacenters [datacenters read as data centers].	CLUSTER	2004	DBLP DOI BibTeX RDF
17	Hangsheng Wang, Li-Shiuan Peh, Sharad Malik	A Power Model for Routers: Modeling Alpha 21364 and InfiniBand Routers.	IEEE Micro	2003	DBLP DOI BibTeX RDF
17	Jiuxing Liu, Weihang Jiang, Pete Wyckoff, Dhabaleswar K. Panda 0001, David Ashton, Darius Buntinas, William Gropp, Brian R. Toonen	Design and Implementation of MPICH2 over InfiniBand with RDMA Support	CoRR	2003	DBLP BibTeX RDF
17	D. Cassaday, K. Dierling, I. Colloff, D. Garcia	High Speed System Area Networks (InfiniBand) - Challenges and solutions.	NCA	2003	DBLP DOI BibTeX RDF
17	Vijay Velusamy, Changzheng Rao, Srigurunath Chakravarthi, Jothi P. Neelamegam, Weiyi Chen, Sanjay Verma, Anthony Skjellum	Programming the InfiniBand Network Architecture for High Performance Message Passing Systems.	PDCS	2003	DBLP BibTeX RDF
17	Jose Renato Santos, Yoshio Turner, G. John Janakiraman	End-to-End Congestion Control for InfiniBand.	INFOCOM	2003	DBLP DOI BibTeX RDF
17	Liran Liss, Yitzhak Birk, Assaf Schuster	Efficient exploitation of kernel access to Infiniband: a software DSM example.	Hot Interconnects	2003	DBLP DOI BibTeX RDF
17	Dhabaleswar K. Panda 0001	Designing Next Generation Clusters with Infiniband: Opportunities and Challenges.	CLUSTER	2003	DBLP DOI BibTeX RDF
17	Ulf Troppens, Rainer Erkens	Speichernetze - Grundlagen und Einsatz von Fibre Channel SAN, NAS, iSCSI und InfiniBand.		2002	RDF
17	Odysseas I. Pentakalos	An Introduction to the InfiniBand Architecture.	Int. CMG Conference	2002	DBLP BibTeX RDF
17	Jose Renato Santos, Yoshio Turner, G. John Janakiraman	Evaluation of congestion detection mechanisms for InfiniBand switches.	GLOBECOM	2002	DBLP DOI BibTeX RDF
17	Dhabaleswar K. Panda 0001	Tutorial 2: InfiniBand Architecture and Where it is Headed.	Hot Interconnects	2002	DBLP DOI BibTeX RDF
17	David R. Follett	Distributed Storage Networking Architectures: Fibre Channel, iSCSI, Ethernet, InfiniBand, Hyper Transport, Rapid IO & 3GIO Collide in the Data Center.	NCA	2001	DBLP DOI BibTeX RDF
17	Greg Pfister	The Promise of InfiniBand for Cluster Computing.	CCGRID	2001	DBLP DOI BibTeX RDF
17	Gregory Pfister	The Future of Cluster Interconnects: InfiniBand or Ethernet?	CLUSTER	2000	DBLP DOI BibTeX RDF
11	Sreeram Potluri, Ping Lai, Karen A. Tomko, Sayantan Sur, Yifeng Cui, Mahidhar Tatineni, Karl W. Schulz, William L. Barth, Amitava Majumdar 0001, Dhabaleswar K. Panda 0001	Quantifying performance benefits of overlap using MPI-2 in a seismic modeling application.	ICS	2010	DBLP DOI BibTeX RDF	MPI-2, one-sided, RDMA, latency hiding
11	Cameron D. Patterson, Steven W. Ellingson, Brian S. Martin, K. Deshpande, John H. Simonetti, Michael Kavic, Sean E. Cutchin	Searching for Transient Pulses with the ETA Radio Telescope.	ACM Trans. Reconfigurable Technol. Syst.	2009	DBLP DOI BibTeX RDF	Direct sampling radio telescope array, FPGA cluster computing, RFI mitigation, signal dedispersion
11	Ping Lai, Pavan Balaji, Rajeev Thakur, Dhabaleswar K. Panda 0001	ProOnE: a general-purpose protocol onload engine for multi- and many-core architectures.	Comput. Sci. Res. Dev.	2009	DBLP DOI BibTeX RDF	Protocol offload/onload, Multi-core, Many-core
11	Rui Machado, Carsten Lojewski	The Fraunhofer virtual machine: a communication library and runtime system based on the RDMA model.	Comput. Sci. Res. Dev.	2009	DBLP DOI BibTeX RDF	Fraunhofer virtual machine, Runtime system, RDMA
11	Philip J. Vardon, Ioana Banicescu, Peter John Cleall, Hywel R. Thomas, Roger N. Philp	Coupled thermo-hydro-mechanical modelling: A new parallel approach.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Kevin J. Barker, Kei Davis, Darren J. Kerbyson	Performance modeling in action: Performance prediction of a Cray XT4 system during upgrade.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Christian Kaiser, Torsten Hoefler, Boris Bierbaum, Thomas Bemmerl	Implementation and analysis of nonblocking collective operations on SCI networks.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Mohammad J. Rashti, Ahmad Afsahi	Improving RDMA-based MPI eager protocol for frequently-used buffers.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Krishna Chaitanya Kandalla, Hari Subramoni, Gopalakrishnan Santhanaraman, Matthew J. Koop, Dhabaleswar K. Panda 0001	Designing multi-leader-based Allgather algorithms for multi-core clusters.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Torsten Hoefler, Timo Schneider, Andrew Lumsdaine	A power-aware, application-based performance study of modern commodity cluster interconnection networks.	IPDPS	2009	DBLP DOI BibTeX RDF
11	Germán Rodríguez, Ramón Beivide, Cyriel Minkenberg, Jesús Labarta, Mateo Valero	Exploring pattern-aware routing in generalized fat tree networks.	ICS	2009	DBLP DOI BibTeX RDF	k-ary n-trees, communication/traffic patterns, extended generalized fat trees (xgft's), network topologies, routing algorithms, clos networks
11	Matthew Small, Xin Yuan 0001	Maximizing MPI point-to-point communication performance on RDMA-enabled clusters with customized protocols.	ICS	2009	DBLP DOI BibTeX RDF	rendezvous protocol, mpi, rdma
11	Ketan Kulkarni, Edgar Gabriel	Evaluating Algorithms for Shared File Pointer Operations in MPI I/O.	ICCS (1)	2009	DBLP DOI BibTeX RDF
11	Xiaolan Joy Zhang, Henrique Andrade, Bugra Gedik, Richard King, John F. Morar, Senthil Nathan, Yoonho Park, Raju Pavuluri, Edward Pring, Randall Schnier, Philippe Selo, Michael Spicer, Volkmar Uhlig, Chitra Venkatramani	Implementing a high-volume, low-latency market data processing system on commodity hardware using IBM middleware.	SC-WHPCF	2009	DBLP DOI BibTeX RDF	IBM middleware, commodity hardware, market data processing, implementation
11	Yen-Jun Chen, Ching-Hsien Hsu, Kuan-Ching Li, Hsi-Ya Chang, Shuen-Tai Wang	Power Consumption Optimization of MPI Programs on Multi-core Clusters.	Infoscale	2009	DBLP DOI BibTeX RDF	MPI, cluster Computing, Power Consumption, multi-core processor
11	Bradley C. Kuszmaul	Brief announcement: TeraByte TokuSampleSort sorts 1TB in 197s.	SPAA	2009	DBLP DOI BibTeX RDF	samplesort, terabyte, cluster, sort, mpi
11	Changjun Hu, Yewei Shao, Jue Wang 0013, Jianjiang Li	Automatic Transformation for Overlapping Communication and Computation.	NPC	2008	DBLP DOI BibTeX RDF	Parallel compiling, Communication optimization, Control-flow analysis, Source-to-source transformation
11	Costin Iancu, Steven A. Hofmeyr	Runtime optimization of vector operations on large scale SMP clusters.	PACT	2008	DBLP DOI BibTeX RDF	communication code generation, parallel programming, program transformations, latency hiding, performance portability
11	Coromoto León, Gara Miranda, Casiano Rodríguez, Carlos Segura	A Distributed Parallel Algorithm to Solve the 2D Cutting Stock Problem.	PDP	2008	DBLP DOI BibTeX RDF	synchronization scheme, load balancing, cutting stock problem
11	Sameer Kumar 0001, Gábor Dózsa, Jeremy Berg, Bob Cernohous, Douglas Miller, Joe Ratterman, Brian E. Smith, Philip Heidelberger	Architecture of the Component Collective Messaging Interface.	PVM/MPI	2008	DBLP DOI BibTeX RDF
11	Mohamad Chaarawi, Jeffrey M. Squyres, Edgar Gabriel, Saber Feki	A Tool for Optimizing Runtime Parameters of Open MPI.	PVM/MPI	2008	DBLP DOI BibTeX RDF
11	Michael Hofmann 0002, Gudula Rünger	MPI Reduction Operations for Sparse Floating-point Data.	PVM/MPI	2008	DBLP DOI BibTeX RDF	reduction operation, MPI, pipelining, performance optimization, run length encoding
11	Jesper Larsson Träff, Andreas Ripke, Christian Siebert, Pavan Balaji, Rajeev Thakur, William Gropp	A Simple, Pipelined Algorithm for Large, Irregular All-gather Problems.	PVM/MPI	2008	DBLP DOI BibTeX RDF
11	Noboru Tanabe, Hironori Nakajo	Introduction to Acceleration for MPI Derived Datatypes Using an Enhancer of Memory and Network.	PVM/MPI	2008	DBLP DOI BibTeX RDF
11	Pavan Balaji, Sitha Bhagvat, Rajeev Thakur, Dhabaleswar K. Panda 0001	Sockets Direct Protocol for Hybrid Network Stacks: A Case Study with iWARP over 10G Ethernet.	HiPC	2008	DBLP DOI BibTeX RDF
11	Jesús Escudero-Sahuquillo, Pedro Javier García, Francisco J. Quiles 0001, José Flich, José Duato	FBICM: Efficient Congestion Management for High-Performance Networks Using Distributed Deterministic Routing.	HiPC	2008	DBLP DOI BibTeX RDF	Congestion Control, Distributed Routing, High-Performance Interconnects
11	Michael Ko, Daniel Eisenhauer, Renato Recio	A Case for Convergence Enhanced Ethernet: Requirements and Applications.	ICC	2008	DBLP DOI BibTeX RDF
11	Katharina Benkert, Edgar Gabriel, Michael M. Resch	Outlier detection in performance data of parallel applications.	IPDPS	2008	DBLP DOI BibTeX RDF
11	Gopalakrishnan Santhanaraman, Sundeep Narravula, Dhabaleswar K. Panda 0001	Designing passive synchronization for MPI-2 one-sided communication to maximize overlap.	IPDPS	2008	DBLP DOI BibTeX RDF
11	Luiz Carlos Pinto, Luiz H. B. Tomazella, Mario A. R. Dantas	Building efficient multi-core clusters for high performance computing.	ISCC	2008	DBLP DOI BibTeX RDF
11	Mohamad Chaarawi, Edgar Gabriel	Evaluating Sparse Data Storage Techniques for MPI Groups and Communicators.	ICCS (1)	2008	DBLP DOI BibTeX RDF
11	Weikuan Yu, Jeffrey S. Vetter	Xen-Based HPC: A Parallel I/O Perspective.	CCGRID	2008	DBLP DOI BibTeX RDF
11	Karthikeyan Vaidyanathan, Ping Lai, Sundeep Narravula, Dhabaleswar K. Panda 0001	Optimized Distributed Data Sharing Substrate in Multi-core Commodity Clusters: A Comprehensive Study with Applications.	CCGRID	2008	DBLP DOI BibTeX RDF	Distributed Shared State, Multi-Core, Data-Centers, High-Performance Networks
11	Gregory L. Lee, Dong H. Ahn, Dorian C. Arnold, Bronis R. de Supinski, Matthew P. LeGendre, Barton P. Miller, Martin Schulz 0001, Ben Liblit	Lessons learned at 208K: towards debugging millions of cores.	SC	2008	DBLP DOI BibTeX RDF
11	Hiroko Midorikawa, Motoyoshi Kurokawa, Ryutaro Himeno, Mitsuhisa Sato	DLM: A distributed Large Memory System using remote memory swapping over cluster nodes.	CLUSTER	2008	DBLP DOI BibTeX RDF
11	Jérôme Vienne, Maxime Martinasso, Jean-Marc Vincent, Jean-François Méhaut	Predictive models for bandwidth sharing in high performance clusters.	CLUSTER	2008	DBLP DOI BibTeX RDF
11	Peter Sanders 0001, Jochen Speck, Jesper Larsson Träff	Full Bandwidth Broadcast, Reduction and Scan with Only Two Trees.	PVM/MPI	2007	DBLP DOI BibTeX RDF
11	Gopalakrishnan Santhanaraman, Sundeep Narravula, Amith R. Mamidala, Dhabaleswar K. Panda 0001	MPI-2 One-Sided Usage and Implementation for Read Modify Write Operations: A Case Study with HPCC.	PVM/MPI	2007	DBLP DOI BibTeX RDF