Evaluation of Manycore Operating Systems Biruk Y. Nidaw Ziho Shin Jung Sung In Kim Young Woo SW Content Research SW Content Research SW Content Research SW Content Research ETRI ETRI ETRI ETRI Deajeon Korea Deajeon Korea Deajeon Korea Deajeon Korea [email protected] [email protected] [email protected] [email protected] Department of Software and Engineering, UST, 217 Gajeong-ro Yuseong-gu, Daejeon, 305350,KOREA SW Content Research Laboratory ETRI, 218 Gajeong-ro, Yuseong-gu, Daejeon, 34129,KOREA than individual clock rates. While there is a great deal of work Abstract—These days the number of processors in computer on programming abstractions for pronouncing parallelism, there systems is increasing in a very fast speed, and different is very little work on the operating systems and services that manufacturers are producing computers with manycore will be needed to support them. processors. In turn, these manycore computer systems require a Manycore is result of technology evolution that existed to new operating system that can solve the problems of commodity have solutions for the gap between memories and computation operating systems. Commodity operating systems originally made speed; the number of transistors per core increased in order to for single, dual or multi-cores systems; they will have lower performance and scalability problem for higher number of cores have better performance, yet the power required for the that are hundreds or thousands in number. In this regard, scholars transistors is not as such small and the instruction level of different research institutions are trying to develop their own paralleling is not flexible solution in performance upgrading. solutions for existing problems among commodity operating Nowadays number of cores per processor increased that did systems and the recently emerging the manycore processor. fill those gaps, yet will increase the complexity and scalability This paper intends to see what those manycore operating problems that let the software will fill these gaps. Let us see: systems are. The main objective of this paper is to compare and Power: this portion is the point that shows end of endless contrast some of manycore operating systems, analyze their scalability. The main reason was power consumption and power experimental results, and give some summarizing concepts. dissipation, which their existence resulting from pushing up the Manycore operating systems are developing from either the frequency of a single core made this path simply not justifiable scratch or the amendment on the existing commodity operating neither of economic and technological viewpoint. There are systems. Operating systems projects that develop a manycore numerous factors essential to the CPU power consumption: operating system from the scratch, need lots of effort, and generally new approaches are applied. They use completely new = + + (1)[2] technical approaches for development of OSes for increased The dynamic power consumption comes from the activity of number of cores. Operating systems like FOS and BarrelFish are logic gates inside a CPU. some examples of operating systems that developed from the = (2)[1] scratch. On the other hand, some operating system projects focus Which is equivalent on commodity OSes problems for increased number of cores. 2 These projects amend commodity operating systems and/or used ≅ . V . (3) them collectively. Therefore, their main task is preparing systems Where = capacitance, = voltage, = Activity Factor that play an important role for this amendment. As compared with and = the switching frequency the above operating system development approach, these approaches are simple and more manycore OSes used it. Both dynamic and short-circuit power consumption are Operating systems like FusedOS, Cerberus and others are such a dependent on the clock frequency, while the leakage current is type of operating systems. dependent on the CPU supply voltage. In this respect, this paper will see the reason behind the Communication: In manycore processors, the inter-memory selection of either of the two approaches. Also will provide and memory-processor communication will increase highlights about the basic structural differences among the exponentially with the increase in the number of cores and existing manycore operating systems, in order to catch the respective caches, which needs a software solution in order to philosophy behind them. have a better performance and minimized latency. Index Terms—Manycore, operating systems, FOS, Corey, Memory: Program execution, which often limited by the FusedOS, Cerberus, BarrelFish, PopcornLinux, memory bottleneck mainly because of this fact that a significant portion of applications always resides in main memory until it I. INTRODUCTION executed by the processor. Multi-core processors can A. Basics of Operating Systems exacerbate problems unless care taken to conserve memory Now we are on the era of manycore, where processing bandwidth and avoid memory contention. performance raising by increasing the number of cores rather ISBN 978-89-968650-7-0 769 Jan. 31 ~ Feb. 3, 2016 ICACT2016 Scheduling: in software design aspect Chip Multi Processers A. The Structure perspective have more challenges than Symmetric multiprocessing which Manycore operating systems either developing from the scratch includes, program or thread scheduling and better load or making some amendments on the existing commodity distribution on the available cores operating system in order to overcome the scalability issue. In solving these and other manycore processor bottlenecks and further problems, many researchers working late, releasing 1) PopcornLinux lots of software solutions, and developing manycore operating systems; the main purpose of this paper is to see the comparison PopcornLinux is a Linux based multi- kernel operating system, among some of the existing manycore operating systems. which targets a platform on which Intel Xeon processors & In this paper, some of the well-known manycore operating Intel Xeon-Phi board connected through PCIe. These two systems had revealed and presented for further comparison different processor cores share access to a common memory. among them in the next chapter. The main impact of this paper This OS bridges the programmability gap in heterogeneous is that it enables to provide brief concept on some of the ISA platforms and provides distributed shared memory manycore operating systems and give general knowledge about transparently to the application. In a multicore box among them. From the comparison result, to give a generalized and an multi-core processors, one selected as Bootstrap processor that immediate information about operating systems in broad and boots up the primary kernel first and secondary kernels and the manycore ones at specific. remaining application processors next. This research paper organized as follows, in the first part of the paper covers basics and the reason why existence of manycore is indispensable, and then after the research contribution listed. On the second part of this paper broadly known manycore operating system structure and features shown, some additional details for each of those well-known manycore operating systems included. Finally, in this paper comparative analysis and conclusion, which addressed. II. THE MANY CORE OPERATING SYSTEMS The Manycore Operating Systems Structures & Features Fig. 1: Heterogeneous-ISA generic hardware model, and In frequent manner, noted that manycore revolution is Popcorn operating system software layout. [3] further ahead of the software, which makes the fundamental Popcorn can run among different kernels that works on “technology gaps”. It is essential to create bridged before different ISAs. Appears as a single OS and enables the kernels applications can fully take advantage of the massive parallelism to communicate each other and create global OS through and high-performance features of multi-core architectures. In this regard, several manycore operating systems are developing message passing. Its main objective is to hide hardware and analyzing for better performance with different features and diversity from application forming an illusion single execution structures. environment. TABLE-1 MANYCORE OPERATING SYSTEMS “Popcorn initializes its namespace that provides a single OS Developer Institution system image and updates them in every time a new kernel PopcornLinux Antonio Barbalace et At ECE, Virginia Tech joins. It adds the CPU namespace to Linux that permits an al. application, to run on a kernel, list the entire kernel and finally migrate to any of them.” [3] FOS David Wentzlaff et al. CSAI Lab. MIT FusedOS Yoonho Park et al IBM Cerberus Xiang S. Haibo et al. PP Institute, Fudan Univ. Cory Silas Boyd-Wickizer et MIT, MS Re. Asia, (Fudan , al. Xi’an Jiaotong) Univ. Adrian Schüpbach et al. CS Dept. ETH Zürich BarrelFish Fig. 2. PopcornLinux kernel- and user-level software layout. [3] 2) Factored Operating System FOS is a manycore operating system that proposes a solution for hardware locks and that separates the execution of application and operating systems. FOS takes scalability as the ISBN 978-89-968650-7-0 770 Jan. 31 ~ Feb. 3, 2016 ICACT2016 first order design constraint, and raises computing problems in The three components of FusedOS are PEC monitor, regard with an increase the number of cores. Linux Hooks and PEC FS module and CL. Each component has In factored OS design principles, utilization of space its own task and interacts