مديريت SPM در سطح سيستم عامل هاي تعبيه شده

چكيده انگليسي :

96 SPM Management at Embedded Operating Systems Level Mohammad Hossein Kiani Mohammad kiani@ec iut ac ir 06 10 2015 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Language Farsi Degree M sc Supervisor Mohammad Ali Montazeri montazeri@cc iut ac ir Advisor Ali Bohlooli bohlooli@eng ui ac ir Abstract Embedded Operating Systems are considered as the main software in an Embedded System In general process management and memory management functions are some tasks of the embedded operating system For example the memory management unit of C OS an open source embedded operating system uses fixed size memory blocks instead of usual memory functions On the other hand Scratch Pad Memory SPM is a small and fast memory that embedded processors use to store data temporarily Actually SPM is an alternative to the cache memory in embedded systems In order to exploit all the advantages of SPM an efficient allocation mechanism must be in place in compiler and operating system In the past few years several SPM management mechanisms have been proposed These methods try to allocate code or data on the SPM that are frequently accessed at run time to improve the performance or energy consumption However in the methods that have been proposed so far the memory allocation mechanisms by the operating system and the allocation of dynamic data data that is created at run time on the SPM have received less attention Moreover deprivation of tasks for SPM allocation in a multi task environment has not sufficiently investigated The purpose of this research is SPM management at operating system level in such a way so that the frequently accessed data are allocated on the SPM It leads to a lower cost of accessing this data and thereby increases the system performance Privation of tasks in a multi task environment for SPM allocation is not addressed To solve this problem a run time memory management approach is proposed that uses annotations of programmer memory management mechanism of C OS and simple paging of general operating systems In summary to avoid excessive overhead on the operating system at runtime to determine which data should allocated on the SPM this approach uses annotations of programmer Moreover due to segmentation of SPM the portion of this memory is provided On the other hand since this mechanism uses memory management policy of C OS dynamic memory requests are broken and thereby big memory size demands on the SPM can be answered To evaluate the proposed method C and Java programming languages were used and also several embedded tasks were selected and modified to adapt this method Experimental results show that all tasks use their slices to improve performance and none of them have been ignored By comparing this method with other methods it was found that the proposed method has less error rate than the similar approaches in allocating data to the SPM It is because of breaking the memory requests On the other hand the proposed method is fully dedicated to the SPM of each task thus smaller amount of data has to be transferred to the main memory from SPM at run time Key words Dynamic memory management SPM C OS Embedded Systems

كياني، محمدحسين

مديريت SPM در سطح سيستم عامل هاي تعبيه شده

مديريت حافظه پويا , حافظه SPM , سيستم عامل ميكروسي