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System noise, OS clock ticks, and finegrained parallel applications (2005)
| Content Provider | CiteSeerX |
|---|---|
| Author | Tsafrir, Dan Etsion, Yoav Feitelson, Dror G. Kirkpatrick, Scott |
| Description | As parallel jobs get bigger in size and finer in granularity, “system noise ” is increasingly becoming a problem. In fact, fine-grained jobs on clusters with thousands of SMP nodes run faster if a processor is intentionally left idle (per node), thus enabling a separation of “system noise ” from the com-putation. Paying a cost in average processing speed at a node for the sake of eliminating occasional processes delays is (unfortunately) beneficial, as such delays are enormously magnified when one late process holds up thousands of peers with which it synchronizes. We provide a probabilistic argument showing that, under certain conditions, the effect of such noise is linearly pro-portional to the size of the cluster (as is often empirically observed). We then identify a major source of noise to be indirect overhead of periodic OS clock interrupts (“ticks”), that are used by all general-purpose OSs as a means of main-taining control. This is shown for various grain sizes, plat-forms, tick frequencies, and OSs. To eliminate such noise, we suggest replacing ticks with an alternative mechanism we call “smart timers”. This turns out to also be in line with needs of desktop and mobile computing, increasing the chances of the suggested change to be accepted. 1. |
| File Format | |
| Language | English |
| Publisher Date | 2005-01-01 |
| Publisher Institution | In Proceedings of the 19th International Conference on Supercomputing |
| Access Restriction | Open |
| Subject Keyword | System Noise Various Grain Size Periodic O Clock Interrupt Smp Node O Clock Tick Major Source Main-taining Control Suggested Change Occasional Process Delay Fine-grained Job Tick Frequency Certain Condition Late Process Indirect Overhead Mobile Computing Parallel Job Parallel Application Average Processing Speed Smart Timer Alternative Mechanism General-purpose Os Probabilistic Argument |
| Content Type | Text |
| Resource Type | Article |
