help: add missed last new line to "internals" topic Caught by test-gendoc.t.

dirstate: make delaywrite sleep until the next multiple of n seconds Rather than sleep for 2 seconds, we sleep until the next even-numbered second, which has the same effect, but makes tests faster. This removes test-largefiles-update as the long pole of the test suite.

dirstate: only invoke delaywrite if relevant This avoids a significant amount of sleeping in some of our longest tests.

dirstate: move delaywrite logic from write to _write This will allow us to be smarter in upcoming patches.

run-tests: show scheduling with --showchannels This gives one line of output per second with one column per -j level that allows analyzing test scheduling problems. First 24 seconds of output at -j 30 looks like this: 0 . 1 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = s. 2 c c o c r l g r s s = c p = c h c a h c g c h c b c c l l c ss 3 h o b o e a e u u u c o a h o e o c g o l h g h u o = a o = s 4 e n s n b r n n b b m t g n l n l w n o e w e n n e r g i . 5 c t o = a g d - r r = m c w v p v . e v g c e c d v x g . m 6 k r l r s e o t e e b a h e e . e . b e . k b k l e t e . p 7 - i e e e f c e p p u n b b r . r . - r . - - - e r e f . o . 8 p b t v - i . s o o n d o d t . t . c t . c s = 2 t n i . r 9 y - e s c l . t - . d - m i - . - . o - . o y r - - s l . t 10 3 p - e h e . s s . l t b r s . s . m s . d m e f s i e . . 11 - e c t e s . . v . e e . . v . v . m v . e r n o v o s . . 12 c r h . c - . . n . 2 m . . n . n . a n . . e a r n n . . . 13 o f e . k u . . . . - p . . - . - . n - . . v m m - . . . . 14 m . c . - p . . . . e l . . s . m . d s . . . e a e . . . . 15 p . k . r d . . . . x a . . i . o . s o . . . - t n . . . . 16 a . h . e a . . . . c t . . n . v . . u . . . m . c . . . . 17 t . e . s t . . . . h e . . k . e . . r . . . e . o . . . . 18 . . a . t e . . . . a . . . . . . . . c . . . r . d . . . . 19 . . d . o . . . . . n . . . . . . . . e . . . g . i . . . . 20 . . s . r . . . . . g . . . . . . . . . . . . e . n . . . . 21 . . . . e . . . . . e . . . . . . . . . . . . 2 . g . . . . 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 . . . . . . . . . . . . . . . . . . . . . . . . . = . . . . ^C Test names read off vertically, beginning with '='. Idle time (not shown) appears as blank space.

tests: avoid duplicate install steps in test-run-tests At several seconds each, this is significantly slowing down the test.