허재혁 교수

This paper describes the polymorphous TRIPS architecture which can be configured for different granularities and types of parallelism. TRIPS contains mechanisms that enable the processing cores and the on-chip memory system to be configured and combined in different modes for instruction, data, or thread-level parallelism. To adapt to small and large-grain concurrency, the TRIPS architecture contains four out-of-order, 16-wide-issue Grid Processor cores, which can be partitioned when easily extr

We propose an organization for the on-chip memory system of a chip multiprocessor, in which 16 processors share a 16MB pool of 256 L2 cache banks. The L2 cache is organized as a non-uniform cache architecture (NUCA) array with a switched network embedded in it for high performance. We show that this organization can support the spectrum of degrees of sharing: unshared, in which each processor has a private portion of the cache, thus reducing hit latency, completely shared, in which every process

Data caches in general-purpose microprocessors often contain mostly dead blocks and are thus used inefficiently. To improve cache efficiency, dead blocks should be identified and evicted early. Prior schemes predict the death of a block immediately after it is accessed; however, these schemes yield lower prediction accuracy and coverage. Instead, we find that predicting the death of a block when it just moves out of the MRU position gives the best tradeoff between timeliness and prediction accur

Abstract: In this paper, we study the space of chip multiprocessor (CMP) organizations. We compare the area and performance trade-offs for CMP implementations to determine how many processing cores future server CMPs should have, whether the cores should have in-order or out-of-order issue, and how big the per-processor on-chip caches should be. We find that, contrary to some conventional wisdom, out-of-order processing cores will maximize job throughput on future CMPs. As technology shrinks, li

We propose an organization for the on-chip memory system of a chip multiprocessor in which 16 processors share a 16-Mbyte pool of 64 level-2 (L2) cache banks. The L2 cache is organized as a nonuniform cache architecture (NUCA) array with a switched network embedded in it for high performance. We show that this organization can support a spectrum of degrees of sharing: unshared, in which each processor owns a private portion of the cache, thus reducing hit latency, and completely shared, in which

Traditional CPUs and cloud systems based on them have embraced the hardware-based trusted execution environments to securely isolate computation from malicious OS or hardware attacks. However, GPUs and their cloud deployments have yet to include such support for hardware-based trusted computing. As large amounts of sensitive data are offloaded to GPU acceleration in cloud environments, ensuring the security of the data is a current and pressing need. As deployed today, the outsourced GPU model i

This paper describes the polymorphous TRIPS architecture that can be configured for different granularities and types of parallelism. The TRIPS architecture is the first in a class of post-RISC, dataflow-like instruction sets called explicit data-graph execution (EDGE). This EDGE ISA is coupled with hardware mechanisms that enable the processing cores and the on-chip memory system to be configured and combined in different modes for instruction, data, or thread-level parallelism. To adapt to sma

The shielded computation of hardware-based trusted execution environments such as Intel Software Guard Extensions (SGX) can provide secure cloud computing on remote systems under untrusted privileged system software. However, hardware overheads for securing protected memory restrict its capacity to a modest size of several tens of megabytes, and more demands for protected memory beyond the limit cause costly demand paging. Although one of the widely used applications benefiting from the enhanced

Abstract We present a novel, hybrid parallel continuous collision detection (HPCCD) method that exploits the availability of multi‐core CPU and GPU architectures. HPCCD is based on a bounding volume hierarchy (BVH) and selectively performs lazy reconstructions. Our method works with a wide variety of deforming models and supports self‐collision detection. HPCCD takes advantage of hybrid multi‐core architectures – using the general‐purpose CPUs to perform the BVH traversal and culling while GPUs

Although cloud computing has emerged as a promising future computing model, security concerns due to malicious tenants have been deterring its fast adoption. In cloud computing, multiple tenants may share physical systems by using virtualization techniques. In such a virtualized system, a software hypervisor creates virtual machines (VMs) from the physical system, and provides each user with an isolated VM. However, the hypervisor, with a full control over hardware resources, can access the memo

This paper explores a new technique called coherence decoupling, which breaks a traditional cache coherence protocol into two protocols: a Speculative Cache Lookup (SCL) protocol and a safe, backing coherence protocol. The SCL protocol produces a speculative load value, typically from an invalid cache line, permitting the processor to compute with incoherent data. In parallel, the coherence protocol obtains the necessary coherence permissions and the correct value. Eventually, the speculative us

As research progresses, the surface texture tool can significantly reduce the cutting heat and cutting force. However, the tool surface texture width, depth, and spacing also have an impact on the cutting performance. Using the Taguchi method and finite element analysis, the changing laws of cutting temperature, pressure, stress distribution, and cutting force were studied. The results showed that the tool texture width had the greatest influence on the cutting performance, followed by the tool

To mitigate excessive TLB misses in large memory applications, techniques such as large pages, variable length segments, and HW coalescing, increase the coverage of limited hardware translation entries by exploiting the contiguous memory allocation. However, recent studies show that in non-uniform memory systems, using large pages often leads to performance degradation, or allocating large chunks of memory becomes more difficult due to memory fragmentation. Although each of the prior techniques

The Tera-op reliable intelligently adaptive processing system (TRIPS) architecture seeks to deliver system-level configurability to applications and runtime systems. It does so by employing the concept of polymorphism, which permits the runtime system to configure the hardware execution resources to match the mode of execution and demands of the compiler and application.

Cloud computing based on system virtualization, has been expanding its services to distributed data-intensive platforms such as MapReduce and Hadoop. Such a distributed platform on clouds runs in a virtual cluster consisting of a number of virtual machines. In the virtual cluster, demands on computing resources for each node may fluctuate, due to data locality and task behavior. However, current cloud services use a static cluster configuration, fixing or manually adjusting the computing capabil