Title
iNPG: Accelerating Critical Section Access with In-network Packet Generation for NoC Based Many-Cores
Abstract
As recently studied, serialized competition overhead for entering critical section is more dominant than critical section execution itself in limiting performance of multi-threaded shared variable applications on NoC-based many-cores. We illustrate that the invalidation-acknowledgement delay for cache coherency between the home node storing the critical section lock and the cores running competing threads is the leading factor to high competition overhead in lock spinning, which is realized in various spin-lock primitives (such as the ticket lock, ABQL, MCS lock, etc.) and the spinning phase of queue spin-lock (QSL) in advanced operating systems. To reduce such high lock coherence overhead, we propose in-network packet generation (iNPG) to turn passive "normal" NoC routers which only transmit packets into active "big" ones that can generate packets. Instead of performing all coherence maintenance at the home node, big routers which are deployed nearer to competing threads can generate packets to perform early invalidation-acknowledgement for failing threads before their requests reach the home node, shortening the protocol round-trip delay and thus significantly reducing competition overhead in various locking primitives. We evaluate iNPG in Gem5 using PARSEC and SPEC OMP2012 programs with five different locking primitives. Compared to a state-of-the-art technique accelerating critical section access, experimental results show that iNPG can effectively reduce lock coherence overhead, expediting critical section access by 1.35x on average and 2.03x at maximum and consequently improving the program Region-of-Interest (ROI) runtime by 7.8% on average and 14.7% at maximum.
Year
DOI
Venue
2018
10.1109/HPCA.2018.00012
2018 IEEE International Symposium on High Performance Computer Architecture (HPCA)
Keywords
Field
DocType
In Network Packet Generation,Critical Section,Synchronisation Primitive,Cache Coherency,Network on Chip,CMP
Ticket lock,Parsec,Lock (computer science),Computer science,Network packet,Critical section,Parallel computing,Thread (computing),Routing protocol,Cache coherence
Conference
ISSN
ISBN
Citations 
1530-0897
978-1-5386-3660-2
1
PageRank 
References 
Authors
0.36
0
2
Name
Order
Citations
PageRank
Yuan Yao1174.67
Zhonghai Lu21063100.12