Chapter 4 - DSpace at Waseda University

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Chapter 5 most of time. Especially, the mm_page_alloc event caused the biggest time latency. Consequently, we can find the events which are occurred latency. 5.5.2 Analysis of HRTimer Latency In this section, we analyze cause of delay in HRTimer and describe a solution based on the analyzed result by KAS. Figure 5.11: Event log of part where delay occurred 70
71 Chapter 5 Figure 5.11 is the data showing the part where HRTimer latency occurred. According to the result of AL, events such as net_socket_sending, net_dev_xmit, and mm_page_alloc have the occurred a lot. These events were operated before the HRTimer event (HRTIMER_SOFTIRQ) was processed and according to the analysis of the kernel source, these events have higher priority than softriq of HRTimer. Figure 5.12 shows the result analyzed based on event logs is Figure 5.11. Figure 5.12 shows how HRTimer analyzes its latency. In the process of executing, between each softirq handler execution, HRTimer softirq (HRTIMER_SOFTIRQ) is executed. We can find that run_hrtimer_softirq() occurred after net_dev_xmit (NET_TX_SOFTIRQ) and mm_page_alloc (BLOCK_SOFTIRQ) that is higher priority than HRTimer softirq. Figure 5.12: One of the reasons of HRTimer latency Therefore, Figure 5.13 shows process of interrupt in timeline. When softriq with high priority is in progress, softriq with low priority cannot be executed. After the high priority softriq is finished, the low priority (HRTimer softriq) is executed.
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Analyzing Real-Time Performance Pro
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to propose a solution for the probl
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2.5 Event Log …………………
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6. Conclusions and Future Work 6.1
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List of Figures 2.1 User-space vs.
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5.12: One of the reasons of HRTimer
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Chapter 1 functions or equipped wit
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Chapter 1 huge losses in cost. For
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Chapter 1 1.3 Contribution When dev
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Chapter 2 Background 2.1 Embedded S
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Chapter 2 memory and to manage syst
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Chapter 2 2.3 Embedded Linux An emb
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Chapter 2 � How often CPU accesse
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Chapter 2 2.6 Problem Analysis Figu
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Chapter 2 � To count time accurat
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Page 42 and 43: Chapter 3 In Figure 3.4, through Me
Page 44 and 45: Chapter 3 Figure 3.6: Event logging
Page 46 and 47: Chapter 4 execution times, and whol
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Page 56 and 57: Chapter 4 4.2.2 Separation Layer Fi
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Page 62 and 63: Chapter 4 Table 4.1: Important para
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Page 68 and 69: Chapter 5 5.1 Timer Latency When a
Page 70 and 71: Chapter 5 mode [31]. In opposite, p
Page 72 and 73: Chapter 5 Figure 5.4 shows the inte
Page 74 and 75: Chapter 5 latency. Figure 5.5 shows
Page 76 and 77: Chapter 5 Figure 5.6 Interface of s
Page 78 and 79: Chapter 5 Table 5.1: Result of Dete
Page 80 and 81: Chapter 5 Table 5.2: Result of Anal
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Page 86 and 87: Chapter 5 Figure 5.16: Result of ex
Page 88 and 89: Chapter 5 5.6 Summary We analyzed l
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Page 92 and 93: Chapter 6 Figure 6.1: Real-Time Arc
Page 94 and 95: Appendix A.1 RTOS Commonly, a goal
Page 96 and 97: Appendix software, real-time OS mus
Page 98 and 99: Appendix critical task and non-crit
Page 100 and 101: Appendix � Portability CABI shoul
Page 102 and 103: Bibliography [1] L. Abeni, A. Goel,
Page 104 and 105: Bibliography [21] C. Yuan, N. Lao,
Page 106 and 107: Bibliography [38] Magdalena Balazin
Page 108 and 109: Bibliography [56] Balakrishnan, S.;
Page 110 and 111: Acknowledgements I would firstly li
Page 112 and 113: Publication List 種類別題名
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