hot spot

Any part of a program that gets executed a large number of times compared to the rest of the code. Common hot spots are tight iterations and low-level functions. Identifying hot spots is considered a good approach to optimizing.

The hot spot of the mouth is the two areas under your tongue on either side of its base, behind the saliva glands. This is the warmest area of your mouth, and is the most accurate place to get a temperature reading to see whether you have a fever. Not dangling from your lips like a freaking cigarette, 'kay?

Transforms from fire truck to robot and back!

PROTECTOBOT: HOT SPOT

FUNCTION: PROTECTOBOT LEADER
"Rust never sleeps, and neither do I."

Likes to be where the action is. Charismatic, inspiring...other Protectobots have trouble keeping up with his non-stop pace. Believes in being maximally operational every moment of one's life. His fire truck hose shoots high-pressure water 1200 feet. As robot, can press 60,000 pounds, uses fireball cannons that shoot bursts of 2000ºF blue flame 1.5 miles. With fellow Protectobots, forms "Defensor".

• Strength: 9
• Intelligence: 7
• Speed: 4
• Endurance: 9
• Rank: 7
• Courage: 9
• Firepower: 7
• Skill: 6

Hot Spot had an awkward name, plus the disadvantage of being redundant with fellow Autobot Inferno, but he was by far the most attractive robot on the Protectobot team. (Let's face it, though, there's only so many ways you can screw up what is essentially a long box with a ladder on top.)

He had the somewhat distinguishing feature of containing the head of the gestalt robot Defensor in the ladder cradle, rather than having it as a separate attachment, plus the Defensor chest piece split into two "wings" that mounted on the side of the fire truck. The end result was that Defensor had that many fewer pieces to lose--hardly a marketable advantage, but a nice feature nonetheless.

hot spot n.

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

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.