@@ -113,8 +113,8 @@ Comparison with Python's Samplesort Hybrid
113113 4377402 262437 262459 416347 1457945 524286
114114 1.99% 1577.82% -0.06% 967.83% -24.01% 774.44%
115115
116- 524288 9205096 9453356 9408463 524468 9441930 2218577 9692015
117- 9278734 524580 524633 837947 2916107 1048574
116+ 524288 9205096 9453356 9408463 524468 9441930 2218577 9692015
117+ 9278734 524580 524633 837947 2916107 1048574
118118 1.88% 1693.52% -0.03% 1026.79% -23.92% 824.30%
119119
1201201048576 19458756 19950272 19838588 1048766 19912134 4430649 20434212
@@ -431,7 +431,7 @@ at-a-time mode.
431431
432432A refinement: The MergeState struct contains the value of min_gallop that
433433controls when we enter galloping mode, initialized to MIN_GALLOP.
434- merge_lo() and merge_hi() adjust this higher when gallooping isn't paying
434+ merge_lo() and merge_hi() adjust this higher when galloping isn't paying
435435off, and lower when it is.
436436
437437
@@ -549,7 +549,7 @@ that merge_lo and merge_hi adjust: the longer we stay in galloping mode,
549549the smaller min_gallop gets, making it easier to transition back to
550550galloping mode (if we ever leave it in the current merge, and at the
551551start of the next merge). But whenever the gallop loop doesn't pay,
552- min_gallop is increased by one, making it harder to transition to back
552+ min_gallop is increased by one, making it harder to transition back
553553to galloping mode (and again both within a merge and across merges). For
554554random data, this all but eliminates the gallop penalty: min_gallop grows
555555large enough that we almost never get into galloping mode. And for cases
@@ -576,6 +576,12 @@ probably a better guess at the final result than either 0 or 9999. But
576576it's unclear how to generalize that intuition usefully, and merging of
577577wildly unbalanced runs already enjoys excellent performance.
578578
579+ ~sort is a good example of when balanced runs could benefit from a better
580+ hint value: to the extent possible, this would like to use a starting
581+ offset equal to the previous value of acount/bcount. Doing so saves about
582+ 10% of the compares in ~sort. However, doing so is also a mixed bag,
583+ hurting other cases.
584+
579585
580586Comparing Average # of Compares on Random Arrays
581587------------------------------------------------
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