23 lines
1.3 KiB
Plaintext
23 lines
1.3 KiB
Plaintext
hot spot
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n. 1. [primarily used by C/Unix programmers, but spreading] It is received
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wisdom that in most programs, less than 10% of the code eats 90% of the
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execution time; if one were to graph instruction visits versus code
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addresses, one would typically see a few huge spikes amidst a lot of
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low-level noise. Such spikes are called hot spots and are good candidates
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for heavy optimization or hand-hacking. The term is especially used of tight
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loops and recursions in the code's central algorithm, as opposed to (say)
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initial set-up costs or large but infrequent I/O operations. See tune ,
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hand-hacking. 2. The active location of a cursor on a bit-map display. Put
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the mouse's hot spot on the ON widget and click the left button. 3. A screen
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region that is sensitive to mouse gestures, which trigger some action. World
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Wide Web pages now provide the canonical examples; WWW browsers present
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hypertext links as hot spots which, when clicked on, point the browser at
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another document (these are specifically called hotlink s). 4. In a
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massively parallel computer with shared memory, the one location that all
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10,000 processors are trying to read or write at once (perhaps because they
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are all doing a busy-wait on the same lock). 5. More generally, any place in
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a hardware design that turns into a performance bottleneck due to resource
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contention.
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