20 lines
980 B
Plaintext
20 lines
980 B
Plaintext
Profiling bru on various systems has shown that in implementations
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without assembly language speedup, bru spends about 25% to 50% of it's
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time computing checksums. Because there are cases where checksum
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computation is not really needed (such as using two "back-to-back"
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bru's to copy a hierarchy, or when the transmission medium can be
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assumed to be perfect), a "fast mode" has been implemented.
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Under fast mode, checksum computations are not performed. Checksums
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are recorded in the archive as zero, and all checksum tests result
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in a valid checksum being found.
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Using the fast mode option -F reduces the amount of user time by
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about 25% to 50% as expected. However, the elapsed time seldom
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changes significantly since bru is usually I/O bound anyway.
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Note that use of the fast mode option defeats many of the
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automatic functions of bru (such as automatic byte swapping)
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and unpredictable results may occur when the transmission medium
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turns out to be imperfect after all.
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