Annotation of src/share/doc/papers/kerntune/4.t, Revision 1.3
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62: .ds RH Conclusions
63: .NH 1
64: Conclusions
65: .PP
66: We have created a profiler that aids in the evaluation
67: of the kernel.
68: For each routine in the kernel,
69: the profile shows the extent to which that routine
70: helps support various abstractions,
71: and how that routine uses other abstractions.
72: The profile assesses the cost of routines
73: at all levels of the kernel decomposition.
74: The profiler is easily used,
75: and can be compiled into the kernel.
76: It adds only five to thirty percent execution overhead to the kernel
77: being profiled,
78: produces no additional output while the kernel is running
79: and allows the kernel to be measured in its real environment.
80: Kernel profiles can be used to identify bottlenecks in performance.
81: We have shown how to improve performance
82: by caching recently calculated name translations.
83: The combined caches added to the name translation process
84: reduce the average cost of translating a pathname to an inode by 35%.
85: These changes reduce the percentage of time spent running
86: in the system by nearly 9%.
87: .nr H2 1
88: .ds RH Acknowledgements
89: .SH
90: \s+2Acknowledgements\s0
91: .PP
92: I would like to thank Robert Elz for sharing his ideas and
93: his code for cacheing system wide names.
94: Thanks also to all the users at Berkeley who provided all the
95: input to generate the kernel profiles.
96: This work was supported by
97: the Defense Advance Research Projects Agency (DoD) under
98: Arpa Order No. 4031 monitored by Naval Electronic System Command under
99: Contract No. N00039-82-C-0235.
100: .ds RH References
101: .nr H2 1
102: .sp 2
103: .SH
104: \s+2References\s-2
105: .LP
106: .IP [Bentley81] 20
107: Bentley, J. L.,
108: ``Writing Efficient Code'',
109: Department of Computer Science,
110: Carnegie-Mellon University,
111: Pittsburgh, Pennsylvania,
112: CMU-CS-81-116, 1981.
113: .IP [Graham82] 20
114: Graham, S., Kessler, P., McKusick, M.,
115: ``gprof: A Call Graph Execution Profiler'',
116: Proceedings of the SIGPLAN '82 Symposium on Compiler Construction,
117: Volume 17, Number 6, June 1982. pp 120-126
118: .IP [Graham83] 20
119: Graham, S., Kessler, P., McKusick, M.,
120: ``An Execution Profiler for Modular Programs''
121: Software - Practice and Experience,
122: Volume 13, 1983. pp 671-685
123: .IP [Ritchie74] 20
124: Ritchie, D. M. and Thompson, K.,
125: ``The UNIX Time-Sharing System'',
126: CACM 17, 7. July 1974. pp 365-375
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