Content deleted Content added
No edit summary Tags: Reverted Visual edit Mobile edit Mobile web edit |
m →Minimization: Fixed grammar Tags: Mobile edit Mobile app edit Android app edit App section source |
||
| (3 intermediate revisions by 3 users not shown) | |||
Line 6:
In [[computer science]], '''synchronization''' is the task of coordinating multiple [[Process (computer science)|processes]] to join up or [[Handshake (computing)|handshake]] at a certain point, in order to reach an agreement or commit to a certain sequence of action.
==Motivation==
The need for synchronization does not arise merely in multi-processor systems but for any kind of concurrent processes; even in single processor systems. Mentioned below are some of the main needs for synchronization:
''[[Fork–join model|Forks and Joins]]:'' When a job arrives at a fork point, it is split into N sub-jobs which are then serviced by n tasks. After being serviced, each sub-job waits until all other sub-jobs are done processing. Then, they are joined again and leave the system. Thus, parallel programming requires synchronization as all the parallel processes wait for several other processes to occur.
''[[Producer–consumer problem|Producer-Consumer:]]'' In a producer-consumer relationship, the consumer process is dependent on the producer process until the necessary data has been produced.
Line 34:
==Minimization==
One of the challenges for exascale algorithm design is to minimize or reduce synchronization.
Synchronization takes more time than computation, especially in distributed computing. Reducing synchronization drew attention from computer scientists for decades. Whereas it becomes an increasingly significant problem recently as the gap between the improvement of computing and latency increases. Experiments have shown that (global) communications due to synchronization on distributed computers takes a dominated share in a sparse iterative solver.<ref>{{cite journal|title=Minimizing synchronizations in sparse iterative solvers for distributed supercomputers |author=Shengxin, Zhu and Tongxiang Gu and Xingping Liu|journal=Computers & Mathematics with Applications|volume=67|issue=1|pages=199–209|year=2014|doi=10.1016/j.camwa.2013.11.008|doi-access=free|hdl=10754/668399|hdl-access=free}}</ref> This problem is receiving increasing attention after the emergence of a new benchmark metric, the High Performance Conjugate Gradient (HPCG),<ref>{{cite web|url=http://hpcg-benchmark.org/|title=HPCG Benchmark}}</ref> for ranking the top 500 supercomputers.
==Problems==
| |||